The use of the serum protein factor XIIIB (F XIIIB) in parentage testing.

Three thousand thirty-eight white and 313 black paternity cases were phenotyped for genetic variants of the coagulation Factor XIIIB (F XIIIB). Gene frequencies obtained by testing with agarose gel isoelectric focusing clearly differentiated the white and black populations. The expected probability of exclusion (P) for white subjects was P = 0.19 and for black subjects P = 0.25. The observed rates of exclusions for F XIIIB in white and black subjects were close to expected values. The results indicate that F XIIIB is a valuable tool in parentage testing, and the procedures are reasonably easy and inexpensive.