What could indicate the presence of sickle cell trait in a patient?

The presence of hemoglobin A (Hgb A) and hemoglobin S (Hgb S) is a definitive indicator of sickle cell trait. In individuals with sickle cell trait, which is a genetic condition where one allele is normal (Hgb A) and the other is mutated (Hgb S), both types of hemoglobin can be detected in the blood. This combination reflects the carrier status of the individual, as they typically do not display the symptoms associated with sickle cell disease, which occurs when two sickle hemoglobin alleles are present (Hgb S/Hgb S).

The identification of Hgb A and Hgb S through techniques such as hemoglobin electrophoresis demonstrates the individual’s ability to produce both normal and abnormal hemoglobin. Thus, this finding is characteristic of sickle cell trait, making it the correct choice in this context.