Health Atlas Medical Biochemistry

What is medical biochemistry?

Medical biochemistry encompasses the study of biochemical, physiological and cellular processes in the human organism. Biochemical analyses can measure components of various materials such as blood (serum, plasma and whole blood).

Some tests can detect the presence of a specific disease with great accuracy, but many tests are very unspecific, and abnormal values alone can not be used as indications of a disease, or the cause of any disease. Often several analyses are performed simultaneously to make the diagnosis of the patient's condition more accurate.

Results

In our data, we find that more than 10.5 million biochemical samples were taken annually from 4.3 million patients. Each sample can consist of one or more analyses (e.g. vitamin D, vitamin B12 and folate), and of those 10.5 million samples, just over 100 million analyses were performed. Nationally, 4% of the analyses were analyzed at a GP’s office, while the proportions of analyses analyzed at private and public laboratories were 34% and 62% respectively.

The number of tests per 1,000 inhabitants (rate) varied considerably between hospital referral areas. The highest number of tests per 1,000 inhabitants was performed in South-Eastern Norway, where the rate was 44% higher than in Northern Norway, which had the lowest rate. 76% more tests were performed on residents in Vestfold hospital referral area compared with Finnmark hospital referral area. The average number of tests per sample varied from 5.9 for residents in Finnmark hospital referral area to just over 11 for residents in Vestfold, Diakonhjemmet and OUS hospital referral areas. As with the other results, the number of analyses per sample is gender- and age-adjusted, and the differences are therefore not due to different gender and age distributions in the hospital referral areas.

Since the figures do not include samples taken from patients admitted to hospital, it is possible that different distributions between outpatient clinics and admissions in the hospital referral areas may affect the results somewhat. However, since outpatient activity and the use of GPs are far greater in scope than the use of admissions, this is not thought to have a decisive impact on the results.

Age and gender

The linechart above shows the proportion of the population for each age and gender who have had a sample analyzed in a laboratory v.s. those analyzed directly at the GP's office. Note that the reason for this division in the figure is that data on samples analyzed at the laboratory and samples analyzed at the GP's office could not be linked. Therefore the sum of the two could result in double counting, which artificially inflate the perception.

The proportion of the population having biochemical samples taken generally increases with increasing age, but the proportion fluctuates somewhat in the different age groups. Over 40% of children aged 1 year received at least one sample per year (most commonly CRP) that was analyzed at the GP's office. For children aged 9, this proportion fell to 20%, before rising to around 40% for both women and men in their 70s.

50% of the female population in their 20s had at least one biochemical sample analyzed in a laboratory. The corresponding proportion for men was approximately 25%. The differences between women and men narrowed towards the end of the 30s, but did not even out until around the age of 60.

There was considerable variation in annual reimbursements paid-out between the referral areas. The difference in reimbursements paid was 40%. The highest reimbursement per capita was for the population of Vestfold and Vestre Viken, at NOK 339, and the lowest was for the population of Nordland, at NOK 241.

If all referal areas had the same level of activity and thus the same reimbursement per capita as Vestfold and Vestre Viken, this would have led to an increase of approximately NOK 265 million annually at the national level. Conversely, annual reimbursement would have been reduced by NOK 270 million if all referal areas had the same level of activity as Nordland.

Annual reimbursement per capita was highest in the South-Eastern Regional Health Authority at NOK 314 and lowest in Northern Norwegian Regional Health Authority at NOK 247. This means that reimbursements paid were 27% higher for the population in the South-East than for the population in the North.

What is PSA?

Prostate-specific antigen (PSA) is a protein produced only in the prostate gland. Increased PSA is seen in diseases of the prostate, such as prostate cancer, benign prostatic hyperplasia (BPH) or inflammatory conditions (prostatitis) (source: Metodebok).

According to Cancer in Norway (2023), more than 60,000 people are living with prostate cancer in Norway, and the incidence of new patients is about 5,500 per year. The PSA test will be used in the assessment and follow-up of symptomatic diseases from the prostate and in cases of clinical suspicion of prostate cancer, as well as in follow-up after treatment of prostate cancer. The test is also used as an annual screening for men in the age group 40-70 years with an increased genetic risk of prostate cancer.

Results

In the period 2021-2023, just over 600,000 PSA tests were performed annually on approximately 400,000 men aged 35-105 years in Norway. The number of PSA tests varied considerably between hospital referral areas. The highest number of tests per 1,000 men was performed in the South-Eastern Norway Regional Health Authority, where the rate was almost 40% higher than in the other three regions. Twice as many PSA tests per 1,000 men were taken annually from residents of Østfold hospital referral area compared with residents of Finnmark hospital referral area. If all hospital referral areas had the same rate as Østfold, more than 200,000 more PSA tests would have been taken per year, which would have led to an increase in reimbursement from Helfo of around NOK 5 million.

Age

Half of those diagnosed with prostate cancer in the period 2018-2022 were 70 years or older. Men under the age of 60 account for approximately 13% of the incidence of prostate cancer in Norway (Cancer Registry of Norway). However, in our analyses, 26% of PSA tests were performed on people under the age of 60. Norway does not have a screening program for prostate cancer for people without an increased genetic risk of prostate cancer, but it is possible that the PSA test is used for screening to some extent.

Repeat tests

About 17% of the PSA tests taken were repeat tests taken within a shorter than recommended interval, i.e. about 99,000 tests are taken per year less than 12 weeks after the patient's last PSA test. The proportion varied from 13% for residents in the Fonna referral area to 19% for residents in the Østfold referral area.

What is CEA?

Carcinoembryonic antigen (CEA) is an immunoglobulin-like protein that is produced in the glandular tissue of almost all the body's glands. Production is greatest in intestinal tissue, and CEA is therefore particularly used as a tumor marker for colorectal cancer. Bowel cancer is the second most common form of cancer in Norway. According to Cancer in Norway (2023), approximately 50,000 people are diagnosed with bowel cancer (prevalence) and there are about 5,000 new cases each year (incidence). There are few benign diseases that result in high CEA values. At the time of diagnosis, approximately half of the patients have elevated CEA. CEA can therefore not be used for screening. The blood test is used for regular monitoring/follow-up of patients with bowel cancer. Checks can be carried out by a GP or in hospital.

Results

In the period 2021-2023, 130,000 CEA tests were performed annually on approximately 85,000 people in Norway. Considering that the test is not suitable for screening, these are high figures. The number of CEA tests per capita varied greatly between hospital referral areas. Most samples were taken in the South-Eastern Norway Regional Health Authority and the Western Norway Regional Health Authority, where the rates were 80% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. Annually, 3.5 times as many CEA samples per 1,000 inhabitants were taken from residents in the Fonna hospital referral area compared with the UNN hospital referral area. If all hospital referral areas had the same rate as Fonna, 70% more samples would have been taken, which corresponds to just under 100,000 more CEA samples per year. This would have led to an annual increase in reimbursement from Helfo of approximately NOK 3.3 million.

There are no known geographical differences in either the prevalence or survival of bowel cancer in Norway, and this cannot therefore explain the differences in the use of CEA tests.

Age

75% of patients are in the 60-84 age group when diagnosed with bowel cancer. In our analyses, we found that around 60% of CEA samples were taken from people in the 60-84 age group, while just over 30% of samples were taken from people under the age of 60 and 10% of samples were taken from people aged 85 or older.

Repeat samples

About 24% of the CEA samples taken were repeat samples taken at intervals shorter than recommended, i.e. approximately 32,000 samples per year are taken less than 12 weeks after the patient's last CEA. The proportion varied from 15% for residents in the Østfold hospital referral area to 35% for residents in the Sørlandet hospital referral area.

What is CA125?

CA125 is a protein produced by cells lining the body cavities, i.e. pleura, pericardium and peritoneum, as well as in normal endometrium. Most pathological processes here can result in increased serum levels, such as liver failure, heart failure, peritonitis or tumor disease spreading to the abdominal or pleural cavity. CA125 levels increase in most people with ovarian cancer, but also in some benign gynecological conditions such as endometriosis and myomas and therefore cannot be used as a screening test. According to the Norwegian national user manual for biochemistry, the use of this test should be limited to the investigation of pelvic tumors and follow-up of ovarian cancer. Approximately 7,000 CA125 samples are taken annually from men. The analysis taken on men is assumed to have a different indication than ovarian cancer.

According to Cancer in Norway, just over 5,000 women are living with ovarian cancer in Norway, and there were just over 500 new cases in 2023. The Choosing Wisely campaign does not recommend the use of tumor markers when there is no known cancer, specific suspicion of a particular cancer type or a strong, underlying predisposition.

Results

In the period 2021-2023, approximately 78,000 CA125 tests were performed annually on about 55,000 women in Norway. There was great variation in the number of CA125 tests between hospital referral areas. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was over 70% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. Almost three times as many CA125 samples were taken annually per 1,000 women living in Fonna hospital referral area compared with Finnmark hospital referral area. There are no known differences in the incidence of ovarian cancer in Norway, so this cannot explain the differences in the use of CA125 samples.

If all hospital referral areas had the same rate as Fonna, 47% more samples would have been taken, corresponding to approximately 36,000 additional CA-125 samples nationally each year. This would have led to an annual increase in reimbursements from Helfo of approximately NOK 1.4 million.

Age

Ovarian cancer is a disease that mainly affects women over the age of 50, but in rare cases younger women can get the disease. Only 4% of women diagnosed with ovarian cancer are under the age of 40 at the time of diagnosis, while in our analyses this age group accounted for 16% of all CA125 samples. The median age of diagnosis of ovarian cancer is 68 years, while the median age of CA125 samples in our analyses was 57 years.

What is Protein Electrophoresis?

Protein electrophoresis is used to detect abnormal proteins in the blood, so-called monoclonal components. The test result is interpreted manually by the laboratory doctor, and this is therefore a resource-intensive analysis for the laboratory.

Protein electrophoresis is mainly done on suspicion or follow-up of multiple myeloma (bone marrow cancer), but also in the diagnosis and control of Waldenström's disease, amyloidosis or other monoclonal disease (MGUS, monoclonal component of uncertain significance) that must be controlled as multiple myeloma can develop. Multiple myeloma is a form of cancer characterized by uncontrolled growth in a specific group of bone marrow cells called plasma cells.

According to Cancer in Norway, there were approximately 560 new cases of multiple myeloma in 2023, and more than 3,500 people are living with this disease. Monoclonal gammopathy is relatively common, probably prevalence is in the order of about 7 per 1000 inhabitants in Norway (approx. 40,000), mainly in people over the age of 50 (source: Tidsskrift for den norske legeforening).

Results

In the period 2021-2023, approximately 135,000 protein electrophoreses were performed annually on just under 95,000 patients in Norway. There was great geographical variation in the use of protein electrophoresis during the period. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was 70% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. Annually, five times as many such samples were taken from people living in the Vestre Viken referral area compared with Finnmark.

If all hospital referral areas had the same rate as Vestre Viken, more than 100,000 additional samples would have been taken nationally each year, amounting to NOK 18.5 million in reimbursement payments from Helfo. According to the annual report for the national quality registry for lymphoid malignancies (2022), there is no geographical variation in the incidence of bone marrow cancer, and there is no difference in five-year survival between the referral areas. Thus, differences in disease incidence do not explain the large geographical variation in the use of protein electrophoresis.

Age and gender

Bone marrow cancer rarely occurs in people under the age of 40 and the average age at diagnosis is 68. Monoclonal gammopathy mainly affects people over the age of 50. The average age of those receiving protein electrophoresis in our data was 62 years, and the proportion of samples taken from people under the age of 40 was 14% for women and 10% for men.

Repeat samples

It is not recommended to repeat protein electrophoresis more frequently than every 8 weeks. The proportion of samples repeated at short intervals varied from just over 10% to just under 25%. There are differences in coding practices for some hospital referral areas, which means that there is some uncertainty associated with the proportion of repeated samples.

What is NIPT?

In NIPT, a blood sample is taken from a pregnant woman to analyze DNA from the fetus circulating in the mother's blood. The test is done in combination with early ultrasound to detect the chromosomal abnormalities trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) or trisomy 13 (Patau syndrome). Following an amendment to the Biotechnology Act in 2020, all pregnant women are allowed to have NIPT performed. Pregnant women who are not entitled to prenatal diagnostics can have the test performed by certain private companies approved by the Norwegian Directorate of Health and must pay for the examination themselves. In that case, the test costs just over NOK 10,000.

From 2022, NIPT became a public health service for all pregnant women aged 35 or older at due date and for pregnant women with special indications for prenatal diagnosis (Norwegian Directorate of Health). This analysis therefore only covers the years 2022 and 2023.

Results

About 12,600 pregnant women (all age groups) had NIPT performed annually in the public health service, which means that NIPT was performed in about 25% of all pregnancies. The proportion of pregnancies where NIPT was performed increased from 2022 to 2023, which may be due to the health authorities taking time to introduce the practice. It is also possible that demand increased because pregnant women became aware of the offer. Some pregnant women who were not offered NIPT through the public health service paid to have it done by private companies. Figures for this are not included in this analysis.

Pregnant women aged 35 years and older

The proportion of pregnant women aged 35 years and older who received NIPT increased from just under 70% nationally in 2022 to just under 80% in 2023. For all but one hospital referral area, the proportion of pregnant women in this age group who had NIPT performed was between 60-80%. The proportion was lowest for residents of Nord-Trøndelag hospital referral area, where 40% of pregnant women in this age group had NIPT performed. Most hospital referral areas saw an increase in the proportion of NIPT tests from 2022 to 2023. In 2023, Diakonhjemmet had the highest proportion of NIPT tests, at around 90%, while Nord-Trøndelag's proportion was still around 40%. The differences between the hospital referral areas with the highest and lowest proportion therefore increased during the period.

Pregnant women aged 18-33 years

NIPT is taken when the pregnant woman is approximately 12 weeks pregnant, and many who are 34 years old when NIPT is taken will turn 35 before their due date and are therefore entitled to NIPT through public health services. It was not possible to link data on the pregnant woman's due date with data on NIPT, and it was therefore not possible to distinguish between pregnant women who turned 35 before the expected date of birth and pregnant women who were still 34 on their due date. We have therefore excluded pregnant women aged 34 years and looked at pregnant women aged 18-33 years at the time of sampling to say something about the extent of NIPT for pregnant women with special medical or social grounds for having this test performed.

For all but one of the hospital referral areas, the proportion of pregnant women in the 18-33 age group who had NIPT performed increased significantly from 2022 to 2023. The proportion of pregnant women aged 18-33 who underwent NIPT was twice as high in the South-Eastern Norway Regional Health Authority as in the Central Norway Regional Health Authority in 2023. The volume for this patient group is small, which increases the likelihood of random variation. However, it is likely that there is variation in the use of NIPT for pregnant women with special medical or social reasons for having this test performed. This may be due to pregnant women requesting the test to different degrees, or because the offer to pregnant women is not equal.

What is TSH?

TSH is secreted from the pituitary gland. The hormone stimulates the thyroid gland to produce and secrete the hormone thyroxine (T4). These hormones help to regulate the cells' metabolism, and the TSH and free T4 tests are taken to diagnose and control metabolic disease. Metabolic tests are among the most frequently ordered tests, as metabolic disease can manifest as fatigue or lethargy - symptoms that many patients present to their GPs with.

Results

In the period 2021-2023, approximately 3 million TSH tests were performed annually on 1.9 million patients in Norway. The prescription register shows that around 250,000 people used medication for metabolic disease, approximately the same number as reported by the Norwegian Metabolism Association. This means that around 13% of those who had a TSH test had a disease that required medical treatment. There was considerable geographical variation in the use of TSH tests during the period.

Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was 40% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. Annually, 65% more samples were taken from residents in Østfold hospital referral area compared with Finnmark hospital referral area.

If all hospital referral areas had the same rate as Østfold, about 520,000 additional samples would be taken nationally each year, which corresponds to an increase of almost 20%. If all hospital referral areas had the same rate as Finnmark, 850,000 fewer samples would be taken each year, or a reduction in reimbursements of NOK 19 million.

TSH and free T4

According to the Choosing Wisely campaign, routine testing of both TSH and free T4 should be avoided when screening for thyroid disease and monitoring and following up diagnosed hypothyroidism, as TSH alone is sufficient in most cases.

In the period 2021-2023, TSH was taken alone in only 17% of the samples. This means that TSH and T4 were taken simultaneously on most occasions. There was great variation between the referral areas, with the proportion of samples with only TSH varying from 1% to 35%. The proportion of samples with only TSH increased slightly in 2023, which is positive, but the proportion of samples where T4 and TSH are taken at the same time should still be reduced considerably.

Repeat samples

About 10% of the TSH samples taken were repeat samples taken at intervals of less than 6 weeks, i.e. approximately 280,000 samples are taken per year less than 6 weeks after the patient's last TSH test.

What is Vitamin D?

Vitamin D measurement is indicated in a small group of patients with calcium metabolism disorders, suspected vitamin D deficiency as in osteoporosis, chronic musculoskeletal pain, chronic kidney disease or conditions with reduced intestinal absorption. When monitoring treatment for vitamin D deficiency, it is recommended that a new sample is taken at an interval of at least 3-4 months after starting treatment or changing dose. There is little vitamin D in the normal diet (found in oily fish, egg yolk, cheese). Sunlight on the skin is our most important source of vitamin D. It is therefore recommended to take supplements in the form of cod liver oil or tablets during the winter months.

Results

In the period 2021-2023, approximately 2 million vitamin D tests were performed annually on just under 1.5 million patients in Norway. In other words, far more patients were tested than there are indications for. More than 10% of the vitamin D samples taken are repeat samples taken at intervals of less than 12 weeks, which means that more than 210,000 samples per year are taken too soon after the last sample.

The number of vitamin D samples varied considerably. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was 65% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. 2.3 times as many samples per 1,000 population were taken annually from residents in Østfold hospital referral area compared with Finnmark hospital referral area. If all hospital referral areas had the same rate as Finnmark, almost 900,000 fewer vitamin D samples would have been taken each year. This would have resulted in a reduction in reimbursements from Helfo of approximately NOK 44 million per year.

Age and gender

About 25% of the female population in Norway aged 20-50 had at least one vitamin D test taken annually. The same applies to around 12% of men. Vitamin D receives a lot of media attention, which may contribute to the strikingly high rate.

Repeat tests

About 11% of the vitamin D tests taken were repeat tests taken at intervals shorter than recommended, i.e. about 211,000 tests are taken per year less than 12 weeks after the patient's last vitamin D test. The proportion varied from 8% for residents of Finnmark hospital referral area to 14% for residents of Bergen hospital referral area.

What is vitamin B12?

A deficiency of vitamin B12, or cobalamin, can cause symptoms from all organ systems, but is most frequently associated with anemia, neurological and psychological problems. The vitamin is only found in animal foods and a diet without or with only small amounts of meat, fish, eggs and milk is therefore associated with cobalamin deficiency. The use of antacid drugs and surgery in the stomach or the last part of the small intestine predispose to a lack of absorption of the vitamin. The incidence of vitamin B12 deficiency increases with age. Vitamin B12 deficiency leads to an accumulation of methylmalonic acid (MMA) and homocysteine. These are therefore considered metabolic markers of vitamin B12 deficiency (source: The Norwegian Medical Association).

Results

In the period 2021-2023, just under 2.4 million vitamin B12 tests were performed annually on 1.7 million patients in Norway. The number of B12 samples per capita varied considerably between hospital referral areas. The highest number of samples per capita was taken in the South-Eastern Norway Regional Health Authority, where the rate was over 40% higher than in the Northern Norway Regional Health Authority, which had the lowest rate.

1.7 times as many samples per 1,000 inhabitants were taken annually from residents in Østfold hospital referral area compared with Finnmark hospital referral area. If all hospital referral areas had the same rate as Finnmark, the number of B12 samples would have been reduced by 800,000 per year. This would have resulted in a reduction in reimbursements from Helfo of approximately NOK 22 million per year.

Age and gender

Each year, approximately 30% of the female population aged 20-50 took B12 at least once. The corresponding figure for men was approximately 15%. The gender differences evened out after the age of 75, at the same time as the proportion of the population who had B12 measured rose to over 50%.

Repeat samples

About 7% of the B12 samples taken were repeat samples taken at intervals of less than 8 weeks, meaning that approximately 165,000 samples per year are taken less than 8 weeks after the patient's last B12 measurement. For many patients, it is unnecessary to repeat the measurement of B12 after a short time.

What is MMA?

Both MMA and homocysteine are established markers of vitamin B12 and folate deficiency, and these two assays are often ordered together. MMA is an amino acid that is dependent on vitamin B12 (cobalamin) to be metabolized into the citric acid cycle. With an adequate supply of B12, MMA in blood shows a stable low level, while B12 deficiency leads to accumulation of MMA. MMA is high in infants and is more weakly associated with B12 deficiency. Increasing MMA values are also seen with increasing age and reduced kidney function.

Results

In the period 2021-2023, approximately 300,000 MMA tests were performed annually on just over 245,000 patients in Norway.

The number of MMA samples per 1,000 population varied considerably between hospital referral areas. Most samples were taken in Helse Vest, where the rate was four times higher than in Helse Nord, which had the lowest rate. During the period 2021-2023, an average of almost 14 times as many samples per 1,000 population were taken annually from residents in Bergen hospital referral area compared with Sørlandet hospital referral area. The bar chart shows that the number of samples per 1,000 population decreased sharply for Bergen hospital referral area during the period. In 2023, the difference between Bergen and Sørlandet hospital referral areas was reduced from 14 to 10 times .

If all hospital referral areas had the same rate as Bergen, the number of MMA samples would have increased by 75%, which corresponds to approximately 220,000 samples per year. This would have resulted in an increase in reimbursements from Helfo of around NOK 12 million per year.

Age and gender

The proportion of the female population aged 20-50 who had MMA measured was twice as large as the proportion of the male population who had the same test. The gender differences narrowed from the age of 50 and evened out by the age of 70.

What is homocysteine?

Both homocysteine and MMA are established markers of vitamin B12 and folate deficiency, and these two tests are often ordered together. Vitamin B12 and folate (vitamin B9) deficiency results in increased homocysteine (Hcy). Otherwise, mutations in several different enzymes can result in high levels of homocysteine in blood and urine. Elevated homocysteine can also be seen in hypothyroidism, kidney failure, SLE, psoriasis, rheumatoid arthritis, malignant conditions and almost all chronic diseases. Homocysteine is reported to be a better marker than MMA for vitamin B12 deficiency in young children (<2 years).

Results

In the period 2021-2023, approximately 323,000 homocysteine tests were performed annually on around 260,000 patients in Norway. There was great variation in the number of homocysteine samples per inhabitant between hospital referral areas. The highest number of samples per 1,000 inhabitants was taken in Helse Vest, where the rate was four times higher than in Helse Nord, which had the lowest rate. During the period 2021-2023, far more homocysteine samples per capita were taken annually from residents in Bergen hospital referral area than in other hospital referral areas. The figure shows that the rate in Bergen was almost twice as high as the rate in Stavanger, which was the second highest. On average, 12 times as many samples per 1,000 inhabitants were taken from residents in Bergen hospital referral area compared with Sørlandet hospital referral area, which had the lowest rate.

If all hospital referral areas had the same rate as Sørlandet, the number of homocysteine samples would have been reduced by 77%, corresponding to approximately 245,000 samples annually. This would have resulted in a reduction in reimbursements from Helfo of almost NOK 14 million per year. If all hospital referral areas had had the same rate as Bergen, this would have led to an increase in reimbursement payments from Helfo of almost NOK 31 million per year.

Age and gender

The proportion of the female population aged 20-50 who had MMA measured was twice as large as the proportion of the male population who took the same test. The gender differences narrowed from the age of 50 and evened out by the age of 70.

What is folate?

Folate deficiency can cause hematological (anemia) and neuropsychiatric changes similar to cobalamin deficiency. Folate is a B vitamin, naturally occurring in green vegetables, meat, liver and eggs. There is an increased need for folate during periods of rapid growth in the life cycle (pregnancy, childhood), but also in diseases with a high degree of cell division (psoriasis). An unbalanced diet, especially in combination with alcohol abuse, and intestinal diseases that cause malabsorption can lead to folate deficiency. A daily intake of folate one month before and during the first 2-3 months of pregnancy has been shown to reduce the risk of developing neural tube defects in the fetus.

Results

In the period 2021-2023, approximately 1.8 million folate tests were performed annually on just over 1.3 million patients in Norway. There was considerable variation between hospital referral areas in the number of folate tests per 1,000 inhabitants. During the period 2021-2023, almost twice as many samples per 1,000 inhabitants were taken annually from residents of Bergen hospital referral area compared with Diakonhjemmet and Lovisenberg hospital referral area. The bar chart shows that the number of samples per 1,000 population increased for Bergen hospital referral area during the period.

If all hospital referral areas had the same rate as Diakonhjemmet and Lovisenberg, the number of folate samples would have been reduced by 26%, which corresponds to approximately 470,000 samples annually. This would have resulted in a reduction in reimbursements from Helfo of approximately NOK 10 million per year. If all hospital referral areas had the same rate as Bergen, this would have led to an increase in reimbursement payments from Helfo of more than NOK 18 million per year.

Age and gender

20-25% of the female population aged 20-50 had folate measured annually, the corresponding proportion for men was 10%. The gender gap narrowed from the age of 50 and evened out by the age of 70, when the proportion of the population who had folate measured annually rose to over 40%.

Repeat samples

About 12% of the folate samples taken were repeat samples taken at intervals shorter than 12 weeks, meaning that approximately 205,000 samples per year are taken less than 12 weeks after the patient's last folate measurement. For many patients, it is unnecessary to repeat the measurement after a short time.

What is cholesterol?

Cholesterol is a fatty substance, and total cholesterol is the total amount of cholesterol in the blood and includes HDL cholesterol and LDL cholesterol. Of the cholesterol in plasma, 60-70 percent is found in the LDL particles, 25-35 percent in the HDL particles. The blood test is used to assess the risk of developing heart disease and vascular disease.

Results

In the period 2021-2023, approximately 1.95 million total cholesterol tests were performed annually on just under 1.4 million patients in Norway. There was considerable variation between hospital referral areas in the number of total cholesterol tests per 1000 population. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was 50% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. During the period 2021-2023, 1.8 times as many samples per 1,000 population were taken annually from residents of Østfold hospital referral area compared with Nordland hospital referral area.

If all hospital referral areas had the same rate as Nordland, the number of total cholesterol tests would have been reduced by 29%, corresponding to approximately 567,000 tests annually. This would have resulted in a reduction in reimbursements from Helfo of just over NOK 5 million per year.

Age and gender

In the 20-45 age group, more women than men receive treatment for cardiovascular disease (Cardiovascular Disease Registry (FHI) 2022). Our analyses show that a slightly larger proportion of women than men in the age group 20-60 years had their total cholesterol measured in the period 2021-2023. The proportion of the population who measured total cholesterol rose steadily from 10% at age 20 to around 35% at age 60. For the age group 60-80 years, the proportion of the population measuring total cholesterol continued to rise, but in this age group the proportion of men who had a test was higher than the proportion of women.

Repeat tests

Choosing Wisely campaign recommends that at least four weeks should pass from the time total cholesterol is measured until the patient has a repeat test. 2% of the total cholesterol samples taken were repeat samples taken within a shorter interval than recommended. This means that approximately 37,000 samples per year were taken less than 4 weeks after the patient's last total cholesterol measurement. For the majority of patients, these tests were probably unnecessary.

What is HDL cholesterol?

HDL cholesterol is often measured to assess the risk of arteriosclerotic cardiovascular disease, especially if cholesterol is elevated or the patient is otherwise at increased risk of arteriosclerotic disease. A high concentration of HDL cholesterol usually means a lower risk of cardiovascular disease.

Results

In the period 2021-2023, just under 2 million HDL tests were performed annually on just under 1.4 million patients in Norway. There was considerable variation between hospital referral areas in the number of HDL tests per 1,000 inhabitants. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was just under 40% higher than in the Northern Norway Regional Health Authority and the Central Norway Regional Health Authority, which had the lowest rate. During the period 2021-2023, 1.6 times as many samples per 1,000 population were taken annually from residents of Østfold hospital referral area compared with Finnmark hospital referral area.

If all hospital referral areas had the same rate as Finnmark, the number of HDL samples would have been reduced by 25%, corresponding to approximately 480,000 samples annually. This would have resulted in a reduction in reimbursements from Helfo of approximately NOK 4.5 million per year.

Age and gender

The proportion of the population who had HDL measured rose steadily with increasing age. Approximately 17% of Norwegian 40-year-olds had their HDL measured annually, while the corresponding figure for 70-year-olds was just over 40%.

Repeat tests

Choosing Wisely campaign recommends that at least four weeks should pass from the time HDL is measured until the patient has a repeat measurement. Approximately 2.5% of the HDL samples taken were repeat samples taken at intervals shorter than 4 weeks, meaning that approximately 50,000 samples are taken per year, which violates the recommendation of a minimum of 4 weeks between HDL measurements.

What is LDL cholesterol?

LDL cholesterol is often measured to assess the risk of arteriosclerotic cardiovascular disease, especially if cholesterol is elevated. It is also measured during follow-up of treatment in patients with known atherosclerotic cardiovascular disease. The risk of cardiovascular disease increases at high values.

Results

In the period 2021-2023, 2 million LDL tests were performed annually on approximately 1.4 million patients in Norway. There was considerable variation between hospital referral areas in the number of LDL samples per 1,000 inhabitants. Most LDL samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was just under 40% higher than in the Northern Norway Regional Health Authority and the Central Norway Regional Health Authority, which had the lowest rate. During the period 2021-2023, 60% more samples per 1,000 population were taken annually from residents in Vestfold hospital referral area compared with Finnmark hospital referral area.

If all hospital referral areas had the same rate as Finnmark, the number of LDL samples would have been reduced by 26%, corresponding to approximately 533,000 samples annually. This would have resulted in a reduction in reimbursements from Helfo of just under NOK 5 million per year.

Age and gender

The proportion of the population who had their LDL cholesterol measured rose steadily with increasing age. Annually, around 15% of Norwegian 40-year-olds had their LDL cholesterol measured, while the corresponding figure for 70-year-olds was just over 40%.

Repeat tests

Choosing wisely campaign recommends that at least four weeks should pass from the time LDL is measured until the patient has the measurement repeated. Approximately 2.5% of the LDL samples taken were repeat samples taken at intervals shorter than 4 weeks, which means that approximately 50,000 samples per year are taken at shorter intervals between LDL measurements than recommended.

What is NT-proBNP?

NT-proBNP is used when heart failure is suspected and to assess the prognosis and effect of heart failure treatment. Natriuretic peptide hormones are found in the heart muscle and are normally secreted in small amounts into the bloodstream. NT-proBNP is an inactive metabolite that has a longer half-life in plasma and is more stable than the active BNP. BNP is produced in increased amounts when the heart muscles are subjected to increased stress, such as in heart failure. The higher the NT-proBNP, the more likely it is that the patient has heart failure. At low values, heart failure can be ruled out with reasonable certainty.

Results

In the period 2021-2023, almost 450,000 NT-proBNP tests were performed annually on approximately 280,000 patients in Norway. There was considerable variation between hospital referral areas in the number of NT-proBNP tests per capita. The highest number of samples per capita was taken in the South-Eastern Norway Regional Health Authority, where the rate was approximately 50% higher than in the Central Norway Regional Health Authority, which had the lowest rate. In the period 2021-2023, three times as many samples per 1,000 inhabitants were taken annually from residents in the Sørlandet hospital referral area compared with the Stavanger hospital referral area.

If all hospital referral areas had the same rate as Sørlandet, the number of NT-proBNP tests would have increased by 67%, corresponding to just under 300,000 tests annually. Reimbursement per NT-proBNP test is relatively high, and 300,000 extra tests would therefore have led to an increase in reimbursements from Helfo of just under NOK 39 million per year.

Age and gender

The proportion of the population who had NT-proBNP measured rose steadily from the age of 50. Annually, 7% of female 70-year-olds had their NT-proBNP measured. The corresponding figure for men was 11%. This proportion doubled up to the age of 80.

Repeat tests

Choosing Wisely campaign recommends that at least one week should pass from the time NT-proBNP is measured until the patient has a repeat measurement. 1.6% of the NT-proBNP samples taken were repeat samples taken at intervals shorter than 1 week.

What is Ferritin?

Ferritin measurement is the most important analysis when investigating iron deficiency. Iron deficiency can lead to anemia and iron excess can lead to iron in internal organs (hemochromatosis) and, in rare cases, damage to these organs. Iron deficiency anemia is a relatively common condition, especially in fertile women, children and elderly men and can be caused by poor diet, but also underlying disease. Ferritin is a large protein that acts as a store for iron atoms (Fe3+). Low values therefore indicate an iron deficiency, while high values usually indicate an iron surplus (hemochromatosis). However, the protein is also an acute phase protein and can be released and give high values in response to inflammatory diseases.

Results

In each of the years 2021-2023, one third of the population had at least one outpatient ferritin test performed. There was great geographical variation in the number of ferritin tests. The South-Eastern Norway Regional Health Authority had the highest number of tests per capita, with a rate 50% higher than the Northern Norway Regional Health Authority, which had the lowest rate. Annually, 75% more samples per 1,000 population were taken from residents in the hospital referral areas of Østfold, OUS and Akershus compared with Finnmark hospital referral area. If all hospital referral areas had the same rate as Østfold, more than 400,000 additional ferritin samples would have been taken each year. This would have resulted in an increase in reimbursement from Helfo of approximately NOK 7.1 million per year.

Age and gender

About 40% of women in their 30s had at least one ferritin test annually during the period. The same applies to around 15% of men. The gender differences evened out at the age of 70, at the same time as the proportion of the population who had a ferritin test rose to 55%.

What is ALAT?

ALAT is considered to be a liver-specific marker and is analyzed in the assessment and control of liver disease, such as hepatitis, toxic or alcohol-induced liver injury, primary liver tumors, liver metastases and biliary obstruction.

Results

In the period 2021-2023, approximately 2.85 million ALAT tests were performed annually on 1.82 million patients in Norway. There was considerable variation between hospital referral areas in the number of ALAT tests per capita. Most samples were taken in the South-Eastern Norway Regional Health Authority, where the rate was approximately 30% higher than in the Northern Norway Regional Health Authority, which had the lowest rate. During the period 2021-2023, 50% more samples per 1,000 population were taken annually from residents in Østfold hospital referral area compared with Nordland hospital referral area.

If all hospital referral areas had had the same rate as Nordland, the number of ALAT samples would have been reduced by 22%, which corresponds to around 620,000 samples annually. This would have led to a reduction in reimbursements from Helfo of approximately NOK 3.1 million per year.

Age and gender

More than 20% of female 20-year-olds in Norway had their ALAT measured each year. The corresponding figure for men was approximately 10%. This proportion rose steadily towards the age of 70, and each year just over 40% of the population over the age of 70 had their ALAT measured.