Optical absorbance-based rapid test for the detection of sickle cell trait and sickle cell disease at the point-of-care

[Display omitted] •The study proposes a rapid low-cost test based on optical absorbance to detect sickle hemoglobin (HbS).•The proposed test can differentiate between sickle cell trait and sickle cell disease.•The proposed test only requires 5 μl of blood and the test result can be obtained in 15 min.•The proposed test has been clinically validated using 438 blood samples from populations susceptible to sickle cell disease.•The proposed test has an average sensitivity of 97% and a specificity of 98.6%. People afflicted with sickle cell disease (SCD) experience severe deterioration in quality of life. The disease is characterized by debilitating pain, anemia, and increased susceptibility to life threatening infections. This genetic disorder is endemic to many parts of the world. Extensive and accurate screening of individuals with sickle cell trait (SCT) in the population, coupled with genetic counselling can inhibit the propagation of the disease. The gold-standard techniques for the detection of sickle hemoglobin, such as capillary electrophoresis, HPLC, and genetic testing, are prohibitively expensive and time-consuming. Mass screening is usually conducted with a low-cost test called the solubility test, which does not offer high specificity. This study proposes a game-changing single-step low-cost method for rapidly yet accurately screening and diagnosing SCD and SCT. This method relies on the hitherto unexplored differences in the optical absorbance between diseased, trait, and normal blood samples, under deoxygenated conditions. The proposed method was tested in two phases of clinical validation: a pilot study and a blind study. A total of 438 patient samples were tested using the proposed method across the two phases. The proposed method offers an average accuracy, sensitivity, and specificity of 97.6%, 96.9%, and 98.6%, respectively. The proposed test has the potential to obliviate the conventional two-step process of screening and diagnostic tests as it can be used at the point-of-care with minimal training and yet yield results reliable enough to assess disability benefit claims.