Fructosamine Test

Diabetes, Hemolytic Anaemia, Sickle Cell Anaemia, Kidney failure

Humans need glucose to produce energy for their body functions. It works by combining sugar with the protein present in the blood to form a glycated protein; this process is called glycation. If the amount of glucose rises in the blood, more protein will combine with the glucose, resulting in the formation of more glycated proteins.

One of the major proteins present in the blood is haemoglobin. When it combines with glucose, it results in the formation of glycated haemoglobin (HbA1c). Haemoglobin also combines with albumin, another major protein in the blood, to form fructosamine. The measurement of the glycated proteins provides an accurate picture of glucose present in the body.

Cells in our blood live in our body for about 120 days. Therefore, the glycated haemoglobin represents the average blood glucose level of about 2-3 months. The test is known as the glycated haemoglobin test. The other blood protein lives in our body for about 14-21 days. So, the glycated protein gives a measurement of the average blood glucose level of 2-3 weeks. The test used for this measurement is known as the fructosamine test. In short, the test measures blood glucose in diabetic people. Please note it is not a screening test but is used when other tests may not be reliable.

The fructosamine test is less commonly used than the glycated haemoglobin test. It is useful in conditions where one cannot use glycated haemoglobin tests like sickle cell anaemia, where the shape of RBC is different. The result of the fructosamine test is also helpful during the pregnancy of a diabetic female. In pregnancy, body hormones frequently change, which can trigger a change in sugar levels. Therefore, it is important to monitor the sugar levels and change the medications accordingly.

Symptoms that indicate high sugar levels are blurred vision, headache, hunger, drowsiness, dry mouth, bloating, shortness of breath, vomiting and confusion. A high sugar level for a very long time can cause heart attack, stroke, loss of vision, damage to eyes, kidneys and other nerve problems. It can also delay the healing of wounds. The results of the fructosamine test and other sugar tests can help the doctor with a treatment plan.

The International Diabetes Federation has found that there were around 72.9 million people with diabetes in India in 2017. It is estimated that there will be around 134 million cases by 2045. The cases are more in urban cities than in rural areas, making it essential to conduct frequent fructosamine tests.

Other names of a fructosamine test

• Serum fructosamine
• Glycated Serum Protein
• GSP

What does the fructosamine test detect or measure and who is this prescribed for?

The fructosamine test measures the levels of fructosamine in the blood, which gives an estimate of the average blood sugar level 2-3 weeks before the test.

It is prescribed if a person is experiencing the following conditions:

• Blurred visions
• Headache
• Dry mouth
• Bloating
• Shortness of breath
• Vomiting
• Confusion
• Feeling drowsy and tired
• Increase in frequency of urination
• Dehydration
• Sudden loss of weight

Over a long period, if sugar levels are high, it can lead to

• Stroke
• Heart attack
• Damage to the eyes
• Kidney problem
• Nerve problems
• Delay in the healing of wounds and infection

People with the complaints mentioned above are prescribed blood sugar tests by consulting a physician. Although the fructosamine test is not a very popular blood sugar test, it is preferable over other tests in some conditions. The conditions where a doctor prescribes fructosamine test are,

• Haemolytic anaemia
• Sickle cell anaemia
• Diabetic pregnancy
• Blood loss
• People with different haemoglobin types have abnormal haemoglobin than normal like HbSS, HbCC and HbSC
• Frequent blood transfusion
• Increase the turnover of RBC
• Thalassemia

There are a few conditions where the results of the fructosamine test are not accurate. In these conditions, a glycated haemoglobin test is preferred. Conditions, where the fructosamine test is not applicable are,

• Thyroid disease
• Liver disease
• Kidney disorders (Nephrotic syndrome)
• Increased immunoglobulin levels (especially IgA)
• Intestinal disease (Protein-losing enteropathy)

The consulting doctor may prescribe the fructosamine test at regular intervals to monitor the sugar level. A single test is not preferable. The doctor will ask to repeat the test to check the trend of sugar level over time. After monitoring the result of the tests, the doctor can change or continue the ongoing medications.

The fructosamine test is applicable for males and females of all age groups. There are certain medicines like vitamin C supplements that can affect the results of the fructosamine test. Talk to your doctor about all the medicines and supplements you are taking.

What is considered a high fructosamine level?

High fructosamine levels are

• levels 175 - 280umol/L in people without diabetes
• The level 210 - 421umol/L in people with controlled diabetes
• A level above 422umol/L in people with uncontrolled diabetes

The high levels of fructosamine test results indicate the presence of excess sugar levels in the blood. The value is the average sugar level of the previous 14-21 days.

The results of the fructosamine test are interpreted on the basis of the suggested reference range, medical history, signs and symptoms and other tests. The normal range is 175-280 umol/L for people without diabetes and 210-421 umol/L for people with controlled diabetes. For people with well-controlled diabetes, the fructosamine test is not suitable as it won’t be as accurate as other tests.

Fructosamine levels above the reference range are considered high. It can be due to the following conditions:

• Uncontrolled Diabetes
• Hypothyroidism
• Infections and inflammatory diseases
• Iron deficiency anaemia
• AIDS

Fructosamine levels below the reference range are considered low. It can be due to the following conditions:

• Low protein levels
• Malnutrition
• A disease of intestine like protein-losing enteropathies
• Nephrotic syndrome
• Low albumin production by the liver
• Hyperthyroidism
• Severe illness or injury
• Pregnancy
• Obesity

The results of the fructosamine test depend upon the blood protein level. If the albumin level decreases, the fructosamine level decreases too. The test results are affected by age, temperature, vitamin C level and the total protein level of the body. Monitoring the trends of fructosamine test value for some time is important to draw any conclusion.

The results of a fructosamine test are based on the analysis of a blood sample.

Test Preparation

The fructosamine test is a blood test that depends on the proteins present in the blood. Therefore, it doesn’t require any fasting or specific preparation. The test can be done at any time of the day. It is a simple procedure that doesn’t require much time. The blood is drawn using a needle from a prominent vein of the forearm. It is collected in a vial or test tube. It is then sent to a laboratory for further testing.

Test inclusions: What parameters are included?

The parameters of the Serum fructosamine test check for the amount of fructosamine in the blood. It is expressed as micromole per litre. The level of fructosamine shows the level of blood glucose level. The higher the level of fructosamine in the blood, the higher the average blood sugar level. The results of the fructosamine test are not expressed as positive or negative.

How frequently should you take this test?

The number of times one should get tested for blood sugar levels depends upon the type of diabetes one has and the medicines one takes. Your doctor will guide you about how often you should get tested. In the case of a pregnancy of a diabetic woman, the doctor will ask for a fructosamine test more frequently.

How reliable is fructosamine?

The fructosamine test is not reliable in cases of

• Chronic kidney disorder
• Thyroid disease
• Liver disease
• Well-controlled diabetes
• Increased immunoglobulin levels (especially IgA) due to infections or inflammations
• Intestinal disease (protein-losing enteropathy)