Objectives: To compare hemoglobin A_1c (HbA_1c) levels in blood samples which were collected

using various types of anticoagulant.

Materials and methods: Blood samples were collected from 30 diabetices patients and 5 healthy volunteers using tubes containing ethylenediaminetetraacetic acid (EDTA), lithium heparin (LH), lithium heparin plus glyceraldehydes (LH+GA), and sodium fluoride (NaF). All blood samples were kept at room temperature (26-28 ^oC) for one to eight hours and then in a refrigerator at 2-8 ^oC for zero to five days before measuring the

HbA_1c levels. HbA_1c levels using Turbidimertic Inhibition immunoassay (TI) and High Performance Liquid Chromatography (HPLC). HbA_1c levels obtained from various types of anticoagulants and at various time points were analyzed and compared using standard statistical methods.

Results: The Mean of HbA_1c levels obtained from EDTA, LH, LH+GA, and NaF blood samples were not significantly different (p>0.05) as measured with either the TI or HPLC methods. The levels of HbA_1c samples prepared with various types of anticoagulants at 1 ^st, 4 ^th,8^th hours (room temperature) and 0, 1^st, 3^th, 5^th days (refrigerator temperature) were not significantly different (p>0.05).

Conclusions: LH, LH plus GA, and NaF anticoagulants did not influence HbA_1c levels in blood samples and can be used instead of EDTA for collecting blood for HbA_1c measurements both TI and HPLC methods. The level of HbA_1c remains stable for at least 8 hours at room temperature and at least 5 days at refrigerator temperature

(2-8 ^oC).