Glycated Albumin Converter
Glycated Albumin Converter
Convert glycated albumin to an estimated HbA1c, and see when GA is more reliable than HbA1c — and when it is not.
Glycated Albumin → HbA1c
Albumin-based estimateGlycated albumin 18%
Formula
- glycated albumin
- the ketoamine-linked, glycated fraction of total serum albumin, %
- 0.297, 2.51
- one published regression relating GA to HbA1c; several similar regressions exist and this one is approximate
- half-life
- albumin's half-life is approximately 20 days, against roughly 120 days for the red cell
Worked example
Glycated albumin 18%
0.297 × 18 = 5.346
5.346 + 2.51 = 7.9% estimated HbA1c
When to reach for glycated albumin instead of HbA1c
| Situation | Effect on HbA1c | Use GA? |
|---|---|---|
| Haemolytic anaemia, haemoglobinopathy | Falsely low or unmeasurable | Yes |
| Dialysis, chronic kidney disease | Unreliable — shortened red cell survival, ESA therapy | Yes |
| Recent blood transfusion | Reflects donor blood, not the patient’s own glycaemia | Yes |
| Pregnancy (2nd/3rd trimester) | Underestimates glycaemia; increased red cell turnover | Yes — GA’s shorter window suits rapid change |
| Nephrotic syndrome, hyperthyroidism | Not directly affected | No — these falsely lower GA |
| Cirrhosis, hypothyroidism | Not directly affected | No — these falsely raise GA |
A shorter window, and a different set of pitfalls
Glycated albumin (GA) measures the fraction of circulating albumin that has undergone the same non-enzymatic glycation chemistry as haemoglobin, expressed as a percentage of total albumin. Because albumin’s half-life is roughly 20 days against the red cell’s roughly 120 days, GA reflects average glycaemia over the preceding two to three weeks rather than the two to three months captured by HbA1c — a genuinely different and complementary window, useful for judging the effect of a recent change in therapy.
It is the marker of choice wherever HbA1c cannot be trusted: haemolytic anaemia and haemoglobinopathies that shorten or alter red cell survival, dialysis patients whose uraemia and blood loss do the same, recent transfusion, and pregnancy, where increased red cell turnover in later trimesters causes HbA1c to understate true glycaemic control.
GA has its own confounders, rooted in albumin turnover rather than red cell biology. Nephrotic syndrome and hyperthyroidism both increase albumin turnover — through urinary loss and increased catabolism respectively — replacing glycated albumin with newly synthesised, unglycated protein faster than usual, which lowers GA independent of glucose control. Cirrhosis and hypothyroidism do the opposite, slowing turnover and raising GA. The regression above is also one of several published equations and should be read as approximate rather than as a precise HbA1c equivalent.
Frequently asked questions
What is glycated albumin used for?
Estimating average glycaemia over the preceding two to three weeks, particularly when HbA1c is unreliable because of altered red cell survival.
How does glycated albumin differ from HbA1c?
GA reflects a shorter window — roughly two to three weeks, set by albumin’s ~20-day half-life — against HbA1c’s two to three months, set by the red cell lifespan.
Can glycated albumin be used in dialysis patients?
Yes, and it is often preferred there. Uraemia, blood loss and erythropoiesis-stimulating agents all distort HbA1c in dialysis patients, while GA is not affected by red cell survival.
What lowers or raises glycated albumin independent of glucose control?
Nephrotic syndrome and hyperthyroidism increase albumin turnover and lower GA; cirrhosis and hypothyroidism slow turnover and raise it — in both cases independent of true glycaemic control.
Related calculators
References
- Freitas PAC et al. Glycated albumin: a potential biomarker in diabetes. Arch Endocrinol Metab. 2017;61(3):296–304.
- Koga M, Kasayama S. Clinical impact of glycated albumin as another glycemic control marker. Endocr J. 2010;57(9):751–62.