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Identification of mismatched fixed specimens with a commercially available kit based on the polymerase chain reaction
1Department of Pathology, University of Southern California School of Medicine, Los Angeles.
Abstract:
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.
Insights
Specimen mix-ups can be investigated using molecular genetic analysis on fixed tissues. A polymerase chain reaction (PCR) assay successfully identified patient tissues, proving effective for resolving potential mismatches.
Area of Science:
- Pathology
- Molecular Genetics
- Forensic Science
Background:
- Specimen mix-ups in healthcare settings pose significant risks to patient safety.
- Current methods for investigating specimen mix-ups often require fresh tissue, limiting their applicability to routinely processed fixed specimens.
Purpose of the Study:
- To evaluate the utility of a commercial polymerase chain reaction (PCR)-based kit for molecular genetic analysis of fixed tissues.
- To determine if this assay can accurately investigate potential specimen mix-ups using routinely obtained fixed tissue samples.
Main Methods:
- A commercial PCR-based kit was used to analyze 21 genotypes at a polymorphic human leukocyte antigen (HLA) locus.
- The assay was applied to 16 cases involving potential specimen mismatches, including small biopsy specimens and "floaters."
Main Results:
- Molecular genetic data were successfully obtained from all 16 fixed-tissue cases, irrespective of tissue size or origin from different hospitals.
- The assay demonstrated the ability to amplify and distinguish between different genotypes, enabling objective investigation of specimen identity.
- The assay completion time of approximately 2 days provided clinically relevant turnaround for mismatch investigations.
Conclusions:
- PCR-based molecular genetic analysis is a viable method for investigating potential specimen mix-ups in fixed tissues.
- This approach overcomes the limitations of assays requiring fresh specimens, offering a practical solution for pathology and clinical laboratories.
- The study validates the use of fixed-tissue molecular genetic analysis for ensuring accurate patient tissue assignment and enhancing patient safety.