Identification of mismatched fixed specimens with a commercially available kit based on the polymerase chain reaction.

Specimen mix-ups inevitably occur and have the potential for great harm. The ability to investigate mix-ups objectively and assign fixed tissues to patients correctly is unfortunately limited, as most such assays require fresh specimens. A commercial kit based on the polymerase chain reaction (PCR) can be applied to the molecular genetic analysis of fixed tissues. This kit, which can amplify and distinguish 21 different genotypes at a polymorphic human leukocyte antigen (HLA) locus, was applied to investigate 16 cases of potential specimen mismatches. The majority of tissues were small and essentially irreplaceable biopsy specimens, and four cases involved minute fragments of potential "floaters." Data were successfully obtained from all 16 cases despite the collection from several different hospitals and the small quantities of tissue. The assay required approximately 2 days for completion; therefore, data were returned within a clinically useful time period. This study provided evidence that molecular genetic assays based on the PCR can be applied to routinely obtained fixed-tissue specimens to investigate potential mismatches.