What is the normal adult hemoglobin composition?

The normal adult hemoglobin composition is characterized primarily by the presence of hemoglobin A (HbA), which accounts for more than 95% of total hemoglobin in an adult. Hemoglobin A2 (HbA2) and fetal hemoglobin (HbF) are present in much smaller amounts. Typically, HbA2 comprises about 1.5% to 3.5% of the total hemoglobin, while HbF is usually less than 1% in healthy adults.

The correct choice accurately reflects these typical proportions seen in normal adult hemoglobin composition. Specifically, it highlights the dominance of HbA (greater than 95%), maintains the amount of HbA2 within its normal range of less than 3.5%, and indicates an HbF level of less than 2%. Understanding these percentages is crucial, particularly in a clinical setting where abnormal elevations in HbA2 or HbF can indicate various hematological disorders.

In contrast, the other choices reflect incorrect percentages or proportions that deviate from the established norms for adult hemoglobin composition.