Influence of HbS levels upon the hematological and clinical characteristics of sickle cell trait.

The variable concentration of HbS in individuals with sickle cell trait led us to study the relationship between HbS level and selected vascular events in 355 hospitalized black men with sickle cell trait. There were significant differences in hemoglobin concentration and mean corpuscular volume found in four groups divided by their HbS level, the lowest proportion of HbS (less than 30%) being associated with the lowest hemoglobin concentration (12.6 g/dl) and MCV (77 fl). The percent HbS did not influence the incidence of pulmonary embolism, thrombophlebitis, myocardial infarction, cerebrovascular accident, or idiopathic hematuria. Our results suggest that HbS level does not influence vascular disease, and while certain hematological alterations occur, they are very unlikely to have any clinical significance. Regardless of the proportion of HbS, sickle cell trait in black men is benign.