A sickle solubility screen is positive. Which next test best distinguishes sickle trait from sickle cell disease and identifies the hemoglobin fractions?
1Erythrocyte sedimentation rate with Westergren method
2Osmotic fragility testing in hypotonic saline
3Hemoglobin analysis such as HPLC or electrophoresis✓ 정답
4Bleeding time by standardized Ivy template method
해설
A solubility screen detects the presence of HbS but does not define the hemoglobin pattern. Hemoglobin separation or analysis quantifies HbS, HbA, HbF, and other fractions needed for classification.