It is known that the presence of hemoglobin S (HbS) affects the determination of hemoglobin A(2) (HbA(2)) levels in clinical samples. We quantitated this effect using the Menarini HA-8160 analyzer and compared with other instruments (HELENA beta-thal quik column, TOSOH HLC-723G7 and BIORAD Variant II) using the HELENA SAS-MX alkaline gel electrophoresis kit as the reference method. The %HbA(2) values from the HA-8160 analyzer and the alkaline gel electrophoresis show a good linear correlation in the absence of HbS. A strong positive bias in the %HbA(2) values from the HA-8160 is apparent in the presence of HbS in the samples, when compared with the alkaline electrophoresis. The analytical imprecision and bias of the three HPLC instruments are comparable both in the presence and absence of HbS. The manual column method shows a lower bias in the absence of HbS but is more affected when HbS is present in the samples.