From the Guidelines
Fructosamine testing should be ordered when you need to assess average blood glucose control over the previous 2-3 weeks, particularly in situations where HbA1c testing is unreliable or impractical, as stated in the most recent guidelines 1. When deciding to order fructosamine tests, consider the following scenarios:
- Conditions affecting red blood cell lifespan, such as hemolytic anemia, recent blood transfusions, hemoglobinopathies like sickle cell disease or thalassemia
- Pregnancy, when rapid changes in glucose control occur
- Evaluating the effectiveness of diabetes treatment changes more quickly than the 2-3 months required for HbA1c changes to become apparent Fructosamine measures glycated serum proteins (primarily albumin), which have a shorter half-life than red blood cells, making it more responsive to recent changes in glucose levels 1. However, results can be affected by conditions that alter protein metabolism, such as liver disease, nephrotic syndrome, or thyroid disorders, so these factors should be considered when interpreting results 1. Normal fructosamine values typically range from 200-285 μmol/L, with higher values indicating poorer glycemic control. It is essential to note that while fructosamine can provide useful information, the evidence base supporting its use is weaker than that for A1C, and it should be used in conjunction with other measures of glycemic control, such as self-monitoring of blood glucose and continuous glucose monitoring (CGM) 1.
From the Research
When to Order Fructosamine Tests
Fructosamine tests are useful in certain situations where HbA1c values may not accurately reflect glycemic control. The following are scenarios where fructosamine tests should be considered:
- In patients with red blood cell disorders, such as hemolytic anemia, where HbA1c values may be falsely low 2, 3
- In patients with discrepancies between glucose measurements and HbA1c values 2
- In patients with rapid glycemic excursions, such as those on corticosteroid therapy or insulin therapy, where fructosamine can provide a more accurate reflection of short-term glycemic control 3
- In patients with chronic kidney disease or other conditions where HbA1c may not be reliable 3
- In pregnant women, where fructosamine can provide a more accurate reflection of glycemic control 3
Key Considerations
- Fructosamine measures the level of glycated albumin in the blood, which reflects glycemic control over a shorter period than HbA1c 4, 5
- Fructosamine is not affected by red blood cell disorders, making it a useful alternative to HbA1c in certain patients 2, 3
- Fructosamine has a lower reagent cost and can be easily automated on conventional laboratory instruments, making it a convenient option for monitoring glycemic control 3
Clinical Utility
- Fructosamine has been shown to be a valid diagnostic biomarker for diabetes mellitus, with a moderate correlation with HbA1c 3
- Fructosamine can provide additional information to HbA1c, particularly in patients with rapid glycemic excursions or red blood cell disorders 4, 3
- The clinical utility of fructosamine is still being evaluated, but it may be a useful tool in certain clinical scenarios 5, 6