Final answer:
The metabisulfite screen causing cells with HbS to sickle is true, as it can be positive for both individuals with sickle cell disease (homozygous recessive) and those with the sickle cell trait (heterozygous).
Step-by-step explanation:
The statement that the metabisulfite screen causes cells with any amount of hemoglobin S (HbS) to sickle is true. In individuals with sickle cell disease, they are homozygous recessive (ss) and all their red blood cells contain the abnormal HbS, leading to sickling of cells. Those with sickle cell trait are heterozygous (Ss) and carry one normal hemoglobin gene and one sickle cell gene. While they usually display no symptoms because they produce both normal hemoglobin (A) and HbS, the presence of HbS can cause some of their cells to sickle during the metabisulfite screen test due to induced low oxygen conditions. Therefore, the metabisulfite screen test can be positive for both individuals with sickle cell disease and those with the trait.