What is the combs test?

What is the combs test?

• A. A test for blood oxygenation
• B. Tests for blood type incompatibility
• C. Tests for bilirubin levels
• D. Test for blood glucose concentration

Answer: (B)

Coombs test detects antibodies that are bound to red blood cells, signaling an immune reaction against those cells due to blood type incompatibility. In newborns, a positive direct Coombs test means maternal antibodies are coating the baby’s RBCs, which is how hemolytic disease of the newborn from Rh or ABO incompatibility is identified. There’s also an indirect Coombs test that screens the mother’s serum for antibodies that could react with fetal RBCs in future pregnancies. So this test is all about antibodies against red blood cells and incompatibility between maternal and fetal blood, rather than measuring oxygenation, bilirubin directly, or glucose.

Coombs test detects antibodies that are bound to red blood cells, signaling an immune reaction against those cells due to blood type incompatibility. In newborns, a positive direct Coombs test means maternal antibodies are coating the baby’s RBCs, which is how hemolytic disease of the newborn from Rh or ABO incompatibility is identified. There’s also an indirect Coombs test that screens the mother’s serum for antibodies that could react with fetal RBCs in future pregnancies. So this test is all about antibodies against red blood cells and incompatibility between maternal and fetal blood, rather than measuring oxygenation, bilirubin directly, or glucose.