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| CLINICAL QUERIES |
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| Year : 2017 | Volume
: 15
| Issue : 3 | Page : 166 |
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Clinical questions: Responses to clinical queries from readers: HbA1C
Nihal Thomas
Professor, Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Vellore, Tamil Nadu, India
| Date of Web Publication | 7-Aug-2017 |
Correspondence Address:
Nihal Thomas
Professor, Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Vellore, Tamil Nadu
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/cmi.cmi_63_17
How to cite this article:
Thomas N. Clinical questions: Responses to clinical queries from readers: HbA1C. Curr Med Issues 2017;15:166 |
You may send your clinical queries to Dr. Tony Abraham Thomas, Editor, CMI Journal, Christian Medical College, Vellore, Tamil Nadu, India.
Question 1
At a peripheral hospital setup where laboratory results may be doubtful, how specific and sensitive is HbA1c to indicate glycemic control? Is HbA1c reliable in a patient with low hemoglobin? Is there a better indicator than HbA1c?
Answer
Indeed, the quality of a test is generally dependent on the assay used and the quality assurance schemes that the laboratory is subject to.
The most reliable method for the assessment of HbA1c is high-performance liquid chromatography (HPLC) which is present only in high throughput laboratories. Hence, in smaller hospitals, one may have to resort to other more lower end technology and cost-effective methods such as affinity chromatography and ELISA.
These methods certainly lack the precision that HPLC has. Since there is little other choice for smaller hospitals, one may have to use these methods and compare them periodically against the HPLC values with a quality assurance scheme of a larger laboratory.
In a patient with low hemoglobin, the HbA1c levels could be adversely effected. In general, from the Indian perspective, iron deficiency anemia is associated with falsely lowered HbA1c levels.
Hemolytic anemias in general have a rapid turnover of red blood cells and could be associated with falsely low HbA1c values. Thalessemia per se is associated with a shift to the left of the HPLC curve and is also associated with a low HbA1c level, so also sickle cell anemia.
Hemoglobin E disorders are associated with falsely high levels of HbA1c. Patients with chronic renal failure can be associated with either falsely high or falsely low HbA1c levels, depending on the type of assay used.
Fructosamine levels are available as an alternative for the HbA1c measurement. This measures glycosylated albumin levels which have a half-life of just a week.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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