Diagnosis of Sickle Cell Disease in Gabon Using Sickle SCAN®: A Point-of-Care Blood Test

Abstract

Background: Sickle cell disease (SCD) is the world’s most common genetic blood disorder. Most infant deaths from SCD occur in sub-Saharan Africa, and the mortality rate is exceptionally high in Gabon in Central Africa. In Gabon, there are limited resources for early and accurate detection of sickle cell or trait conditions. Most affected individuals reside in low-resource areas where access to diagnostic testing is often very limited. The most commonly used diagnostic methods require trained staff, adequate infrastructure, electric power, and enough time to perform the analysis. These requirements do not currently allow mass screening to be performed in remote areas of Gabon. The purpose of this pilot study is to develop a standardized screening procedure for SCD in order to determine its prevalence in the southeast area of Gabon by using a rapid and reliable test that does not require significant resources, such as the Sickle SCAN® device. Methods: The accuracy of the Sickle SCAN® device was assessed based on testing 272 blood samples. The exact hemoglobin was identified in 100% of the samples. The test comprises three proprietary indicators that detect the presence of hemoglobin A, S, and C, thus allowing the user to rapidly distinguish between normal (HbAA, N=142), carrier (HbAS, N=41), and sickle cell disease (HbSS, N=88; HbSC, N=1) samples. Hemoglobin variants (S and C) were confirmed by capillary electrophoresis (MinicapR; Sebia). The sensitivity and specificity were calculated for each phenotype. Results: The Sickle SCAN® test analysis revealed the following normal and abnormal phenotypes, including sickle cell trait (HbAS=14,71%) and SCD [HbSS (32.35%) and HbSC (0,74)]. There are no false positives in Sickle SCAN® result for the presence of hemoglobin variant, compared to gold standard approaches to capillary electrophoresis. The estimated sensitivity of the Sickle Scan® test was 92.2%, 100%, and 100% for HbSS, HbAS, and HbSC, respectively. The specificity exceeded 88.23% for all phenotypes (HbSS, HbAS, and HbSC). Conclusion and Implications for Translation:The Sickle Scan® device was found to be reliable with a sensitivity of 92.2%, 100%, and 100% for HbSS, HbAS, and HbSC, respectively. The specificity exceeded 88% for all phenotypes.