Evaluation of conditions associated with glycated hemoglobin values below the reference range.
BACKGROUND
Evaluation of conditions associated with glycated hemoglobin (HbA1c) values below the reference range in HbA1c determinations.


METHODS
Over a time period of 5 years, HbA1c results were determined with the ion-exchange high-performance liquid chromatography (HPLC) method HA-8140 Menarini.


RESULTS
Of approximately 20 000 HbA1c results analyzed, 9 were below the reference range. The reason for HbA1c values below the reference range was found to be liver cirrhosis in 6 patients, anemia with hematological neoplasms in 2 patients, and elevated fetal hemoglobin > 1.5% in one patient. The silent hemoglobin (Hb) variant Hb Graz in 6 patients, Hb Sherwood Forest in 1 patient, homozygote HbS in one patient, and gross hypertriglyceridemia in one patient demonstrated no HbA1c result.


CONCLUSIONS
In patients with liver cirrhosis, HbA1c measurements should be used with caution when evaluating long-term glucose control, and samples with suspected Hb variants should be analyzed by hemoglobin electrophoresis. Our study underscores the need for clinical laboratories and physicians to be aware of the limitations of their HbA1c assay methods as well as of the importance of visual inspection of ion-exchange chromatograms to detect HbA1c values below the reference range and abnormalities caused by the interference factors described here.
Schnedl
Wolfgang J
WJ
Dept. of Internal Medicine, Medical University of Graz, Graz, Austria. w.schnedl@dr-schnedl.at
Lahousen
Theresa
T
Krause
Robert
R
Wallner
Sandra J
SJ
Piswanger-Soelkner
Claudia
C
Lipp
Rainer W
RW
D000740:Anemia / Q000097:blood* / Q000150:complications; D002851:Chromatography, High Pressure Liquid / Q000379:methods / Q000592:standards; D002852:Chromatography, Ion Exchange / Q000379:methods / Q000592:standards; D005319:Fetal Hemoglobin / Q000032:analysis*; D006442:Glycated Hemoglobin / Q000032:analysis*; D019337:Hematologic Neoplasms / Q000150:complications* / Q000473:pathology; D006455:Hemoglobins, Abnormal / Q000032:analysis; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood* / Q000473:pathology; D012016:Reference Values; D012189:Retrospective Studies
D005319:Fetal Hemoglobin; D006442:Glycated Hemoglobin; D006455:Hemoglobins, Abnormal