There are plethora of data on the concordance or dis-concordance between Fasting Blood Glucose and Hb1Ac in the clinical diagnosis of Type 2 Diabetes (T2D). Which of the two assay or test is the most specific and sensitive in the diagnosis of T2D
Implications of measuring HbA1c versus fasting blood glucose level
Fasting blood sugar (FBG) seems more reliable to identify diabetic from non-diabetic subjects than HbA1c. In the case of being interested in using HbA1c in screening, the conventional cutoff point of 6% is an acceptable threshold for discrimination of diabetics from non-diabetics (1).
The American Diabetes Association Guidelines use the following criteria for diagnosis of diabetes mellitus: A random plasma glucose of 200 mg/dL (11.1 mmol/L) or higher in a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, or. A hemoglobin A1c (HbA1c) level of 6.5% (48 mmol/mol) or higher. When the levels are equivocal, a combination of any of the 2 results can be used (2).
Whereas, FBG is a predictor of short-term (28 days) mortality (3), the risk of long-term diabetic complications is best judged by HbA1c (4).
1. Article A Comparison of HbA1c and Fasting Blood Sugar Tests in Gener...
2. https://pubmed.ncbi.nlm.nih.gov/33298413/
3. Article Fasting blood glucose at admission is an independent predict...
4. Article The relationship between hemoglobin a1c and chronic complica...
Fasting blood sugar is more reliable to identify diabetic from non-diabetic subjects than HbA1c.
There is a recent publication in the Lancet that I think you will find interesting.
J.S. Knudsen et al. Changes in type 2 diabetes incidence and mortality associated with introduction of HbA1c as diagnostic option: A Danish 24-year population-based study. Lancet Regional Health Europe 2022; Vol 14
“In conclusion, we found that the incidence of T2D doubled while T2D mortality nearly halved between 1995 and 2011. After the 2012 shift in diagnostic policy, we saw a marked decline in T2D incidence and a higher mortality, probably driven by a shift in the case-mix of diagnosed T2D patients and fewer patients with a baseline HbA1c of
The current gold standard for diabetes screening is the glycohemoglobin test (HbA1c) . It is a general gauge of diabetes control that specifies an average blood glucose level over a few months. It measures glucose that sticks to hemoglobin inside red blood cells.
https://www.healthline.com › new-di...
New Diabetes Test More Accurate - Healthline
HbA1c is sensitive tool for screening for prediabetic (Impaired fasting glucose and Impaired glucose tolerant) . However it may be falsely low in conditions like anaemia , thalassemia , CKD and falsely high in Polycythemia