Point-of-Care Device Accurately Rapidly Diagnoses Sickle Cell Disease

Hemoglobinopathies are the most common autosomal hereditary disorders. Approximately 7% of the global population carries hemoglobin gene mutation including structural hemoglobin variants like sickle hemoglobin or thalassemia.

Sickle cell disease is a major public health problem in India. Lack of rapid and reliable diagnostic methods result in many avoidable deaths in affected population. Current diagnostic tools are laboratory based, expensive and need trained manpower. Early diagnosis is crucial to initiating life-saving therapies and knowledge of sickle cell carrier status is critical to prevention and parental planning for at-risk populations.

Medical Scientists at the ICMR-National Institute of Research in Tribal Health (Jabalpur, India) screened a total of 1,050 patients by sickle cell solubility, hemoglobin (cellulose acetate) electrophoresis, high-performance liquid chromatography (HPLC) and the Gazelle point-of-care device. Sickle positive samples were also confirmed by HPLC using Beta-thalassemia (betathal) short program (VARIANT II, Bio-Rad Laboratories, Inc., Hercules, CA, USA). HPLC and standard cellulose acetate electrophoresis were considered to be the reference standard for comparisons.

Gazelle (Hemex Health, Portland, OR, USA) is a single-use cartridge-based test that enables rapid, affordable, quantitative, accurate diagnosis for both sickle cell anemia (SCA) and carrier status at the point of care. It is a cellulose acetate-based microchip electrophoresis system within a portable instrument, utilizing the principle of standard electrophoresis method with inbuilt analysis software, electronic data storage, and wireless data transmission capabilities. The test provides actionable quantitative hemoglobin information from a finger stick blood sample during the patient visit in less than 10 minutes.

The investigators reported that of the total 1,027 test results obtained, 960 tests were “Valid” (93.5%) and included in the analysis. Gazelle identified all patients with disease (HbSS and Thalassemia Major) with 100% accuracy. Gazelle demonstrated 100% sensitivity when comparing sickle cell disease (SCD) versus sickle cell trait and SCD versus normal. Specificity was 98.9% and 99.5% when comparing SCD versus trait and trait versus normal, respectively. Specificity was 99.8% when comparing SCD versus normal and sensitivity was 99.3% when comparing trait versus normal. Overall, Gazelle yielded a high accuracy (99.0%) compared to reference standard tests (hemoglobin electrophoresis and HPLC).

The authors concluded that Gazelle is a low-cost, rapid diagnostic test with high accuracy for detecting SCD both quantitatively and qualitatively. Gazelle can be a potential screening tool for the rapid diagnosis in resource limited settings and developing countries with high burden of hemoglobin disorders. The study was published on October 13, 2021 in the journal Frontiers in Medicine.

Related Links:
ICMR-National Institute of Research in Tribal Health
Bio-Rad Laboratories
Hemex Health