What is need of this patch?
The indication of a soldier’s type of blood is a necessity. To provide emergency aid to the wounded, medical personnel must know his blood type. There might be no opportunity to test blood a in the field (or in the absence of time).
In recent wars and local conflicts special blood type patches increasingly began to appear in addition to dog tags. The patches allow to assist a wounded soldier faster.
The blood type is written in Latin letters: 0 , A, B, AB, or Roman numerals: I, II, III, IV.
Rh factor may be labeled in various ways: Rh +, POS, + for positive, and Rh-, NEG, – for negative.