The indirect Coombs test finds certain antibodies that are in the liquid part of your blood (serum). These antibodies can attack red blood cells but are not attached to your red blood cells. The indirect Coombs test is commonly done to find antibodies in a recipient's or donor's blood before a transfusion. A test to determine whether a woman has Rh-positive or Rh-negative blood (Rh antibody titer) is done early in pregnancy.
Allele frequency, or gene frequency, is the relative frequency of an allele (variant of a gene) at a particular locus in a population, expressed as a fraction or percentage. Specifically, it is the fraction of all chromosomes in the population that carry that allele.
When the allelic frequency in a population reaches 1.0, the allele is the only one left in the population, and it becomes fixed for that allele. The other allele is permanently lost. In populations in which an allele has become either fixed or lost, the process of random genetic drift stops at that locus. Without further input (mutation), the populations that have allelic frequencies of 1.0 or 0 for either allele will maintain those allelic frequencies forever.