Key words: sickle, trait, hemoglobin S.

Sickle-cell trait (SCT) is the heterozygous state of the sickle cell gene.[1] The prevalence of sickle cell disease reaches up to 16% of the population in the South of Iraq.[2] Reported incidence of SCT in Bahrain is about 11% ,3 and among Omani women is 9.1%.[4]

SCT contrary to common beliefs is not always a benign condition.[4] It has been associated with increased mortality during physical exertion in athletes and non-athletes, reduced exercise tolerance during long-distance running, increased coronary risk and coronary bypass graft surgery, heightened risk of renal carcinoma, thrombo-embolism and death during prolonged air flight, and a 10-fold increase in the risk of hemorrhagic stroke.[5] Differentiating this condition from other sickle syndromes is mandatory to take certain precautions during surgical procedures and other stressful situations, to detect rare but important complications.

The use of high-performance liquid chromatography (HPLC), which facilitates quantification of the various haemoglobin types, may help in subclassification of the sickle syndrome and make diagnosis of SCT easier.[6]

The aim of this study is to give hemoglobin S (HbS) levels in SCT in Basrah (Southern Iraq), which is the discriminating test for diagnosis.

This was a cross sectional hospital based study for patients with sickling disorder who attended the hematology center for screening. From each patient 5 ml of blood was taken in an EDTA tube and the test performedwithin 3-4 days, in the teaching hospital in Basrah. Patient samples were studied by HPLC on a Bio-Rad Variant 2 instrument (Bio-Rad Laboratories, Hemel Hempstead, Hertfordshire) to do quantitative assessment of haemoglobins F, A, A2, and S. The study was done in the years 2000-2005.

A diagnosis of SCT was made if patients had both haemoglobin A and HbS, with the proportion of haemoglobin A being greater than that of HbS. [7,8]

The total number of patients was 647, of them 248 were males and 363 were females.

Mean ±SD of HbS for males was 33.5±5.5% versus 33.4±6.2 % for females, and for both sexes 33.4±5.9% (Table 1). While for hemoglobin F for males was 1.5±1.5% versus 1.4±2.8% for females, and for both sexes 1.5±2.3%. In most of patients (69.3%), the HbS range 31-40 %(Table 2). Only 5.7% of patients were having HbS >40%.

DISCUSSION

Mean level of HbS in our study for both sexes was 33.4±5.9 % among SCT .In Iraqi,Al-Shawi TS , found mean ±SD of HbS to be 34±6.2 in males with SCT in a study of army recruits .9 Previous study from Basrah concentrated on a trimodal distribution of the amounts of HbS, but no exact range value was given.10 In general the level of HbS in SCT ranges from 20-50%11 with a mean value of 38 ± 5 %.12,13In Jordan, the HbS level among SCT was 39.8± 3.8%.14 In conclusion: we for the first time reported the level of HbS among both sexes with SCT in Basrah.