A hemoglobin solubility test is positive. What additional testing is required to distinguish sickle cell trait from sickle cell disease?
1Osmotic fragility testing performed at several saline concentrations
2Direct antiglobulin testing with both anti-IgG and anti-C3
3Hemoglobin electrophoresis or a comparable separation method✓ 정답
4Reticulocyte count with a corrected percentage
해설
A positive solubility test only shows that an abnormal hemoglobin is present; it does not quantify it. Trait and disease are distinguished by the proportion of hemoglobin variants, so a separation method such as electrophoresis is required. This question contrasts screening with confirmation.