Nanda S et al. - The relationship between HbA1c values and mean plasma glucose allows estimation of expected HbA1c. Significant discrepancy between expected and measured HbA1c should be evaluated. Considering Hb variants, evaluating for the same and estimating HbA1c with the appropriate method under such circumstances are described. Numerous new or rare Hb variants will be diagnosed if suspicion is appropriately entertained.