de Haas van Dorsser, F. J., S. Lasano, et al. (2007). “Pregnancy diagnosis in cats using a rapid, bench-top kit to detect relaxin in urine.” Reprod Domest Anim 42(1): 111-2.
Relaxin is a pregnancy-specific hormone in the queen, produced by the placenta. At least one company produces a blood test for pregnancy in cats based on relaxin. This study aimed to determine if urine could be used for rapid diagnosis of pregnancy using a simple in-house kit. The kit was able to detect pregnancy using urine samples from 28 days after mating, with some samples testing positive as early as 21 days. This opens the possibility that a commercially available kit could be marketed for the easy and rapid diagnosis of pregnancy in domestic cats. Similar work has also been published for the leopard (Panthera pardus).
>> PubMed Abstract
de Haas van Dorsser, F. J., W. F. Swanson, et al. (2006). “Development, validation, and application of a urinary relaxin radioimmunoassay for the diagnosis and monitoring of pregnancy in felids.” Biol Reprod 74(6): 1090-5.