The direct Coombs reaction (direct Coombs) is used to test blood before transfusion. It can also be used to detect cases of red blood cell sensitization after taking certain medications or after transfusions. In cases of suspected erythroblastosis fetalis, the test may be used to determine the presence of antibodies in the red blood cells of the newborn.
In some diseases, such as infectious mononucleosis and systemic lupus erythematosus, as well as Rh-sensitization, antibodies are produced by the body that can bind to the patient's red blood cells. The direct Coombs reaction is used to determine whether these antibodies are bound to the patient's red blood cells (positive reaction) or not (negative reaction).
A common cause of a positive result in the direct Coombs reaction is autoimmune hemolytic anemia in which the patient develops antibodies against self red blood cells.
What Do Pathological Values Mean?
- Positive direct Coombs reaction: Rheumatoid arthritis, erythroblastosis fetalis, hemolytic anemia (autoimmune, drug-induced), infections, neoplasms, renal disorders, systemic lupus erythematosus, reaction to transfusions, and in the elderly.
- Drugs that may cause a positive direct Coombs reaction (possibly due to red blood cell sensitization): ampicillin, captopril, cephalosporins, chlorpromazine, chloropropamide, ethosuximide, hydralazine, indomethacin, insulin, isoniazid, levodopa, mefenamic acid, melphalan, methyldopa, para-aminosalicylic acid, penicillin, phenylbutazone, phenytoin, procainamide, quinidine, quinine sulfate, rifampicin, streptomycin, sulfonamides, tetracyclines.
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
