Of course, no tests to establish blood type is very difficult, and sometimes impossible, but the probability of such an establishment is (but still in the future, we recommend that you contact the medical facility to Refine the results, because to identify the blood group on the professional level can only specialists using special equipment in the presence of your blood).
Review the stamp in his passport. Many people is a special note about the blood in the form of a print, wherein the RH factor and the corresponding group.
View his medical records, if the previous step did not return any results.

Find out the blood type of your parents. You should know that if both parents have the I, II, etc. blood, respectively, and the child born from them will have the same blood group. If one of the parents has I, and the second, for example, II blood group, the baby could inherit one of them and, accordingly, either I or group II.
Determine or clarify the extract from a medical card to which group the indicator is your blood. Among these signs distinguish 0, A and B. depending on this, determine your blood group. So 00 is the first blood group, 0A – the second group of blood, 0V – AV the third and fourth.
Remember, to correctly identify the blood group and RH factor can only be a specialist-a medic in a special laboratory, examining your results.