Effective immediately, the Medical Genetics Laboratories at Baylor College of Medicine will discontinue test code 4572 – Hypoxanthine-Guanine Phosphoribosyltransferase (HPRT) Enzyme Analysis in red blood cells. A critical reagent for the assay is no longer available from the manufacturer; as a result, the lab cannot continue to perform this test. We will continue to offer HPRT enzyme test on skin fibroblast (test code 4573) and for prenatal testing (test code 4570). Also, test code 4220-Urine Purine Panel is available for the diagnosis of HPRT enzyme deficiency.