Specimen Provenance Complications in the Biopsy Evaluation Process

Standard identification systems usually ensure that biopsy material is correctly associated with a given patient. Sometimes, as when a tumor is unexpectedly found, the provenance (proof of origin) of a tissue sample may be questioned; the tissue may have been mislabeled or contaminated with tissue from another patient. Techniques used to confirm tissue provenance include comparing either tissue markers of gender or ABO blood groups; however, these methods have weak confirmatory power. Recently, the use of DNA-based polymerase chain reaction (PCR) techniques has been reported. Paired, formalin-fixed, paraffin-embedded, 10 microns tissue sections were selected from 17 patients, 8 of whom had carcinoma, either by dividing a biopsy section, using sequential biopsies, or sequential biopsy and autopsy tissue. The resulting 36 samples were coded before analysis. In two additional cases, 1-mm fragments of tumor from one patient were included in the tissue block of benign tissue from another patient, the tumor fragments were identified on hematoxylinand-eosin-stained sections, separately scraped off the glass slide, and analyzed. Tissue from two clinical cases, one of suspected mislabeling and 10 American Journal of Clinical Pathology 1996 Dec; 10696):758-764 http://www.ncbi.nlm.nih.gov/pubmed/8980351 SPECIMEN PROVENANCE COMPLICATIONS NOV 2010 11 © 2010 DIAGNOSTIC ID, LLC one with a suspected carry-over of malignant tissue were also investigated. Short tandem repeat sequences (STR) or microsatellites, are 2-5 base pair repeats that vary in their repeat number between individuals. This variation (polymorphism) can be assessed using a PCR. A panel of markers of 3 STRs; ACPP, INT 2, and CYP 19 (on chromosomes 3, 11, and 15, respectively) were used. DNA was isolated from the samples after xylene deparaffinization and proteinase digestion, and was then amplified in a radioactive PCR using primers selected to give a product size ranging from 136-178 bases. Amplified products were electrophoresed on denaturing polyacrylamide gels, dried, and autoradiographed. DNA segments were successfully extracted from all samples but one, which was fixed in Bouin's fluid. By comparing allele sizes from the panel, all tissue pairs (other than the Bouin's pair) were successfully matched, the 1-mm tumor fragments were correctly assigned, and the two clinical problems were solved. STRs are highly informative and robust markers, well suited to PCR of small portions of tissue sections, and are an effective method to confirm the provenance of benign and malignant biopsy and autopsy material. V. Method to Prevent Adverse Patient Outcomes Due to Specimen Provenance Complications As identified in this paper, DNA “fingerprinting” has been advocated to establish specimen provenance even among those systems which adopt precise error reduction programs (e.g. RFID or bar-coding). This DNA testing, known by various names, is offered by Mayo Clinic, Cleveland Clinic, Johns Hopkins and the Indiana University Medical Center, for example. For the purposes of this paper, we shall refer to this test as DNA Specimen Provenance Assay (DSPA). The utilization of DSPA PRIOR TO INITIATING TREATMENT is a method to prevent adverse patient outcomes (ie. overtreatment / undertreatment) due to Specimen Provenance Complications. Only by developing a DNA profile from a reference sample from a patient and matching it to the DNA profile from a tissue sample from the patient can a physician be certain that the tissue is that of the patient. And only by performing DSPA matching prior to the initialization of treatment can patient safety be assured and quality of care improved. Performing such a test post-treatment does not increase patient safety. SPECIMEN PROVENANCE COMPLICATIONS NOV 2010 12 © 2010 DIAGNOSTIC ID, LLC THE KNOW ERROR® SYSTEM One system that incorporates both error reduction measures AND DSPA is the know error® system developed by Diagnostic ID, LLC. The know error® system employs both bar-coding AND DSPA confirmation in a prospective process which, when adopted by pathology labs and their referring physicians, establishes specimen provenance, and ,in so doing, eliminates any adverse patient outcomes due to SPCs. HOW THE KNOW ERROR® SYSTEM WORKS Tagging: The know error® system biopsy kits employ patient specific ID codes or “tags” in the form of two-dimensional bar-codes. Each kit is assigned a unique bar-code number (both human and computer readable), and every individual component of the kit is tagged with the matching code -the benefit of which is a system for consistent patient identification and a reduction of errors. DSPA Testing: Included in the know error® system kits are cotton swabs (“buccal swabs”) used to obtain a DNA reference sample from the patient by swabbing the inside of his or her check. This is the very first step in the know error® system’s biopsy protocol, and establishes the initial link between the patient and the assigned kit’s unique number – at both an administrative and molecular level. After self-identification by the patient, the buccal swabs are sent directly to a forensic DNA lab where they are accessioned and stored. Once a comparison with pathology tissue is ordered by the physician, the biopsy tissue used by the pathologist for diagnosis is sent to the forensic DNA lab whereby DNA is extracted and then compared with DNA extracted from the buccal swab having the identical bar-code tag. A DSPA report is issued within 5 business days of receipt of the tissue indicating whether or not specimen provenance has been established. DSPA tests are performed via PCR (polymerase chain reaction) and electrophoresis techniques developed for the forensic identification of biological materials. Unlike visual inspection of hand-written patient records, tissue slide labels, and pathology reports, forensic DNA matching provides an absolute and unambiguous confirmation of identity. The benefit of DNA 11 The protocol examines the same 16 genetic loci as those commonly used for forensic identification by the FBI and other international authorities. These loci and techniques represent the international gold-standard for human identification in the forensic community SPECIMEN PROVENANCE COMPLICATIONS NOV 2010 13 © 2010 DIAGNOSTIC ID, LLC matching is establishing specimen provenance, thus, helping to prevent adverse patient outcomes.