Blood typing is a method of determining a person's blood type by serological methods. It is important to know your blood type for various reasons. In case of blood transfusions, organ transplantation, pregnancy etc., knowing one's blood type is very crucial for various medical purposes. These blood types depend on whether or not there are certain antigens on the red blood cells & if there are antibodies to these substances in your blood. Some of these methods are Laboratory based while some are home based & are available in the form of easy-to-use kits. A range of Laboratory based tests are available nowadays, including:

? Direct Coombs test: This test determines the presence of antibodies to the red blood cells & allows detection of baby's blood cell destruction by an antibody reaction (Rh, Kell, etc.).

? Indirect Coombs test: This test can screen for minor blood factors & presence of antibodies. It is always done on an Rh- mother. This test detects the presence of antibodies (anti-Rh and others) only. If the Indirect Coombs comes up positive, Rh antibody titer test is necessary to determine the type and level of antibody in the blood type.

? Rh antibody titer: If an Indirect Coombs test comes back positive, this test determines the type and quantity of antibodies in the blood. Since the anti-Rh is the most sensitizing, they are the ones most likely to rise during the pregnancy and cause problems. Depending on the level of other antibodies (e.g. anti-Kell) these antibodies could cause hemolytic problems in the baby and need to be monitored. It is usually repeated several times during pregnancy (at 32, 36, & 38 weeks).

? Keihauser-Betke stain: In any case where a possibility of blood mixing is suspected, the Kleihauser-Betke stain should be done. It checks for fetal blood cells in the mother's system and is usually done only when excessive fetal transfusion is suspected. It determines if the mother needs more than one injection of Rhogam.

Such home blood type testing kits are now available in the market and due to the ease of their use, they are quite popular. They usually work on the principles of immuno-precipitation and involve antibodies attached to a solid matrix in the form of strips & detection is facilitated by calorimetric assays.

There are certain home based tests that help in determining blood types without drawing blood. In 80% of the population, blood group antigens are also present in the saliva. In such groups, ABO blood types can be detected using their saliva instead of blood. Such kits are also based on the same principles of immuno-precipitation.

While Laboratory based methods are usually extensive in nature for advanced diagnostics of potential hoemolytic problems associated with agglutination, home based kits on the other hand are quite simple in nature & approach for they usually are limited to detection of few antigens only. Although lab based tests are far more reliable and accurate than the home based tests but home based tests are far easier to conduct. With just few drops of blood, you can find out your blood type within minutes. So for rapid & easy analysis, such kits certainly come handy.