Conditions associated with very low values of glycohaemoglobin measured by an HPLC method
- 1Clinical Pathology Department, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- 2Endocrinology Division, Hospital de Clínicas de Porto Alegre
- Correspondence to: Dr J L Gross Serviço de Endocrinologia, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcellos, 2350 Prédio 12, 40 andar, Porto Alegre, RS, Brazil, 90035-003; jorgegrossterra.com.br; jcamargohcpa.ufrgs.br
- Accepted 30 May 2003
Abstract
Aims: To identify the causes of very low glycohaemoglobin (GHb) values in a sample of patients with diabetes in southern Brazil using high performance liquid chromatography.
Methods: Between August 1996 and December 2001 all samples from patients with diabetes at a university hospital with GHb values below the reference range (4.7–6.0% HbA1c) were submitted to cellulose acetate electrophoresis. Medical records were reviewed to identify conditions that might be associated with these low values.
Results: Among 29 657 samples analysed, 130 patients had GHb < 4.7%. Seventy three patients (56%) were heterozygous for HbS, HbC, or HbD (19 black, two mulatto, and 52 white patients). The other 57 patients (44%) without Hb variants had low haematocrit and haemoglobin values (42 patients) or other conditions such as pregnancy, lipaemia, malignancy, cirrhosis, acetylsalicylic acid use, and absence of diabetes (15 patients).
Conclusions: The presence of an Hb variant may falsely lower GHb measurements. However, anaemia is also a source of negative interference. The haematological status should be considered for the correct interpretation of GHb results.
- CV, coefficient of variation
- DCCT, Diabetes Control and Complications Trial
- GHb, glycohaemoglobin
- Hb, haemoglobin
- HbA1c, glycated haemoglobin
- HPLC, high performance liquid chromatography
