Medical Laboratory Professions and Certification in Canada Practice Exam

Agglutination testing is the standard method for determining blood type because it relies on the interaction between antibodies and specific antigens present on the surface of red blood cells. When blood is mixed with antibodies that are specific to particular blood group antigens, such as A or B antigens, agglutination—or clumping—occurs if those antigens are present in the blood sample. This clumping indicates the presence of the corresponding blood type.

For example, if a sample is mixed with anti-A serum and agglutination occurs, the blood type is identified as type A. This method is both rapid and straightforward, making it practical for clinical laboratories to identify blood types accurately.

In contrast, other methods like enzyme-linked immunosorbent assay (ELISA) are designed primarily for detecting proteins or other substances in a liquid sample, not specifically for blood typing. PCR testing is a molecular technique that amplifies DNA and is useful for various genetic assays but does not directly evaluate blood type. Centrifugation, while essential for preparing samples and separating components of blood, does not determine blood type directly; it simply helps in obtaining a clear sample for further testing. The efficiency and reliability of agglutination testing make it the preferred approach