Assessment of glycemia in diabetes mellitus: hemoglobin A1c.

The monitoring of glycemia is an essential component of diabetes care. It may be divided into self-monitoring of blood glucose (SMBG), which measures the immediate level of glycemia, and measurement of hemoglobin A1c (HbA1c), which reflects longer-term glycemia. SMBG was discussed in an earlier review. HbA1c is a measure of erythrocyte hemoglobin glycation, and since erythrocytes have about a 120 day life span, HbA1c reflects mean glycemia for the previous 3 months (weighted to the most recent month). There are several conditions that confound the HbA1c measurement such as hemolytic anaemia (lowers HbA1c) or aplastic anaemia (raises it), but in most circumstances HbA1c is a valid index of glycemia. The recommendation is to measure HbA1c every 3-6 months, and treat to a target level of < 7%. If these recommendations were successfully followed in most people with diabetes, long-term complications, especially microvascular complications, would be markedly reduced.

Assessment of glycemia in diabetes mellitus--self-monitoring of blood glucose.

Self-monitoring of blood glucose (SMBG) is an integral component of diabetes self-care and, if use optimally, essential to obtaining glycemic control. There are many methods currently available and the use of glucometers can provide readily available information on blood glucose patterns over time. However, some barriers to the use of SMBG, such as its cost, are significant. Other barriers, such as pain, patient denial or insufficient encouragement from the health care professional, should be overcome. While we find pre-prandial testing to be more informative, there are instances where post-prandial testing may be useful such as in pregnancy or in patients with early stages of glucose intolerance. In the future, continuous glucose monitoring will become available, and ultimately an insulin delivery device will be linked to continuous monitoring making the "closed loop" artificial pancreas a reality. At present, SMBG is an under-utilized but important part of modern diabetes care and should be recommended for all people with diabetes.