Presence of CKD leads to underestimation of diabetes when HbA1c is used. Presence of iron deficiency anemia overestimates HbA1c. Hemolytic anemias underestimate HbA1c. Age increases HbA1c by a factor of 0.4. For the moment, limitations of HbA1c may be kept in mind. Can understanding protein binding lead to modification in glycation patterns, and help in designing new therapies? - Time will tell.