Unit Converter
Fructosamine
(Short-Term Glycemic Marker – Reflects Average Glucose Over 2–3 Weeks)
Synonyms
- Fructosamine
- Glycated serum proteins (GSP)
- Glycated albumin fraction
- Ketoamine-linked albumin
- Short-term glycemic index
Units of Measurement
- µmol/L
- mmol/L
Unit Conversions
1 mmol/L = 1000 µmol/L
(Most laboratories report in µmol/L)
Description
Fructosamine refers to glycated serum proteins, predominantly glycated albumin, formed when glucose non-enzymatically binds to serum proteins.
Because serum proteins have a shorter half-life (≈14–21 days), fructosamine reflects:
- Average blood glucose over the past 2–3 weeks
- Shorter-term glycemic control compared to HbA1c (8–12 weeks)
It is especially useful when HbA1c is unreliable.
Physiological Role
Fructosamine itself has no biological function.
It is simply a measurable indicator of recent glycation of serum proteins.
Clinical Significance
High Fructosamine
Indicates:
- Poor glycemic control (past 2–3 weeks)
- Hyperglycemia
- Uncontrolled diabetes
- Pregnancy-related diabetes
- Steroid-induced hyperglycemia
Associated Risks:
- Rapid glucose fluctuations
- Increased complications
- Need for therapy adjustment
Low Fructosamine
May occur in:
- Hypoproteinemia
- Nephrotic syndrome
- Cirrhosis
- Severe malnutrition
- High protein turnover
- After recent albumin infusion
Also falsely low when total serum protein is reduced.
Reference Intervals
(Tietz 8E + AACE + Mayo + ARUP)
Typical Reference Range
- 205 – 285 µmol/L (non-diabetic adults)
Interpretation
| Fructosamine (µmol/L) | Interpretation |
| <205 | Hypoglycemia, low proteins, or good control |
| 205–285 | Normal, non-diabetic |
| 286–320 | Borderline high; mild hyperglycemia |
| 321–375 | Moderately high; poor control |
| >375 | Significant hyperglycemia (poor control) |
| >450 | Very poor control, high-risk |
Values vary slightly by method and laboratory.
Clinical Uses
1. Glycemic Monitoring When HbA1c Is Unreliable
Use fructosamine in patients with:
- Hemoglobinopathies (SCD, thalassemia)
- Hemolytic anemia
- Recent blood transfusion
- Pregnancy
- CKD with altered erythrocyte lifespan
- Post-acute changes in glucose therapy
2. Rapid Assessment of Therapy Adjustments
Useful for monitoring:
- Insulin titration
- Medication changes
- Steroid-induced hyperglycemia
3. Pregnancy & Gestational Diabetes
Reflects short-term glucose status when quick adjustments are needed.
4. Neonatal Diabetes
Helpful in babies where HbA1c cannot be used.
Correlation with HbA1c (approximate)
(Not a true conversion but clinically used guidance)
| Fructosamine (µmol/L) | Approx. HbA1c (%) |
| 205 | 5.5% |
| 245 | 6.5% |
| 285 | 7.5% |
| 345 | 9.0% |
| 400 | 10–11% |
Note: These correlations vary by protein status.
Analytical Notes
- Serum sample
- No fasting required
- Measured by colorimetric nitroblue tetrazolium (NBT) assay or enzymatic methods
- Hemolysis and lipemia may interfere
- Low serum albumin reduces fructosamine independent of glucose
Clinical Pearls
- Fructosamine reflects the previous 2–3 weeks, ideal for rapid monitoring.
- Use fructosamine when HbA1c is unreliable.
- Low albumin falsely lowers fructosamine — always check serum protein.
- In pregnancy, fructosamine correlates better with maternal glucose trends than HbA1c.
- Fructosamine tracks improvements much faster after therapy changes.
Interesting Fact
Fructosamine (glycated protein) formation was first identified in the early 20th century and paved the way for understanding HbA1c as a long-term marker.
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Diabetes Markers.
- ADA & AACE Guidelines - Glycemic Monitoring.
- IFCC Recommendations - Glycation Markers.
- Mayo Clinic Laboratories - Fructosamine.
- ARUP Consult - Diabetes Testing.
- MedlinePlus / NIH - Fructosamine Test.