A rapid, inexpensive and disposable point‐of‐care blood test for sickle cell disease using novel, highly specific monoclonal antibodies

Abstract

Sickle cell disease (SCD) is a significant healthcare burden worldwide, but most affected individuals reside in low-resource areas where access to diagnostic testing may be limited. We developed and validated a rapid, inexpensive, disposable diagnostic test, the HemoTypeSC^™ , based on novel monoclonal antibodies (MAbs) that differentiate normal adult haemoglobin (Hb A), sickle haemoglobin (Hb S) and haemoglobin C (Hb C). In competitive enzyme-linked immunosorbent assays, each MAb bound only its target with <0·1% cross-reactivity. With the HemoTypeSC^™ test procedure, the sensitivity for each variant was <5·0 g/l. The accuracy of HemoTypeSC^™ was evaluated on 100 whole blood samples from individuals with common relevant haemoglobin phenotypes, including normal (Hb AA, N = 20), carrier or trait (Hb AS, N = 22; Hb AC, N = 20), SCD (Hb SS, N = 22; Hb SC, N = 13), and Hb C disease (Hb CC, N = 3). The correct haemoglobin phenotype was identified in 100% of these samples. The accuracy of the test was not affected by Hb F (0-94·8% of total Hb) or Hb A₂ (0-5·6% of total Hb). HemoTypeSC^™ requires <1 μl of whole blood and no instruments or power sources. The total time-to-result is <20 min. HemoTypeSC^™ may be a practical solution for point-of-care testing for SCD and carrier status in low-resource settings.