Screening for Sickle-Cell Trait at Accession to the United States Military

Condition Definition SCT is a heterozygotic carrier state in which an individual has one copy of the normal HbA gene and one copy of the HbS variant. Commercial tests for SCT have been available since the early 1970s. The sickle solubility test qualitatively detects the presence of HbS by precipitating sickle hemoglobin in the presence of an oxygen depleting reagent. With a sensitivity approaching 99% and a specificity of 100%, sickle solubility provides an accurate screening method. The hemoglobin electrophoresis test is a confirmatory test that quantifies the percentage of HbS and is therefore able to distinguish among the HbS disorders, such as SCT or sicklecell disease. According to the 59th Clinical Lab Flight at Joint Base San Antonio-Lackland, Texas (oral communication, November 2013), the U.S. Air Force (USAF) spends $4.86 on the sickle solubility test and $9.41 on the hemoglobin electrophoresis test.