What does the Coombs test evaluate for?

The Coombs test evaluates the presence of antibodies that are bound to the surface of red blood cells. This test is commonly used in the context of diagnosing conditions like hemolytic anemia, where the immune system mistakenly attacks and destroys its own red blood cells. The test can be either direct or indirect. The direct Coombs test checks for antibodies that are already attached to red blood cells, while the indirect test looks for antibodies that are present in the serum but not attached to red blood cells. Identifying these antibodies is essential for determining the underlying causes of anemia or for blood compatibility before transfusions.

Other options, while they pertain to important health evaluations, do not relate to the Coombs test's focus on antibodies associated with red blood cells. For instance, blood glucose levels are evaluated with a different set of tests specific to metabolic conditions like diabetes, and the functional capacity of the heart might be assessed through echocardiograms or stress testing, which are unrelated to the Coombs test. Similarly, the assessment of viral infections typically involves serology or PCR tests, which do not involve the detection of antibodies on red blood cells.