Human Serum Coombs Antisera (Antihuman Globulin Reagent)

Blood banking operates on a fundamental requirement that most people never think about until something goes wrong. Every unit of blood transfused must be confirmed compatible with the recipient's immune system. Every pregnant woman screened for antibodies that could harm her unborn child. Every suspected case of hemolytic anemia investigated for antibodies attacking the patient's own red blood cells. None of this happens without Coombs antisera making the invisible antibodies visible. Human Serum Coombs Antisera is the reagent that makes antiglobulin testing possible in blood banks and immunohematology laboratories worldwide. This is antihuman globulin (AHG) reagent used in both direct and indirect antiglobulin tests (Coombs tests) to detect antibodies and complement components bound to red blood cell surfaces or present free in serum. The reagent is produced by immunizing animals (typically rabbits) with human immunoglobulins, which induces production of polyclonal antibodies specific for human IgG antibodies and complement factor C3d. When added to washed red blood cells coated with IgG or complement, the antihuman antibodies bind to the human antibodies and form bridges between adjacent sensitized cells, causing visible agglutination. The direct antiglobulin test (DAT) detects antibodies or complement already bound to red blood cell surfaces in vivo. This test is critical for diagnosing autoimmune hemolytic anemia, investigating hemolytic transfusion reactions, and diagnosing hemolytic disease of the fetus and newborn. The indirect antiglobulin test (IAT) detects free antibodies circulating in serum or plasma. This test is essential for pre-transfusion antibody screening, crossmatching blood units for compatibility, and prenatal antibody screening in pregnant women. Polyspecific Coombs antisera (like the green-colored reagent shown) contains antibodies against both IgG and C3d complement, providing broad-spectrum detection. When the polyspecific reagent produces a positive result, monospecific antisera (anti-IgG alone or anti-C3d alone) are used for follow-up testing to characterize whether red cells are coated with IgG antibodies, complement, or both. This differentiation is clinically important because it helps determine the cause and clinical significance of the positive test. The reagent is typically dyed green using patent blue and tartrazine to allow easy visual identification during laboratory workflows where multiple reagents are used simultaneously. Storage at 2-8°C maintains reagent potency until the expiration date printed on the bottle, typically 18 to 24 months from manufacture. The reagent contains sodium azide (0.1% w/v) as a preservative, which inhibits bacterial growth but requires careful handling and disposal. Each dropper bottle delivers approximately 40 microliters per drop, allowing precise volumetric dosing during testing. The reagent must not be diluted and should not be used if turbid, as turbidity indicates bacterial contamination or protein aggregation that will compromise test performance. For distributors supplying blood banks, hospital transfusion services, reference immunohematology laboratories, and donor screening centers, Coombs antisera represents an essential reagent with consumption directly tied to transfusion volume and prenatal screening programs. Sara Wellness has been exporting immunohematology reagents and blood banking supplies from India for 15 years.