Detection of clonal IGH gene rearrangements: Summary of Molecular Oncology Surveys of the College of American Pathologists

Context. - The diagnosis of B-cell lymphoid malignancy can frequently be substantiated by detecting clonal immunoglobulin heavy chain (IGH) gene rearrangements, which is typically done by polymerase chain reaction (PCR) amplification and/or Southern blot analysis. Objective. - To characterize current laboratory practice for the assessment of IGH rearrangements and to identify opportunities for improvement. Design. - The data from the Molecular Oncology Proficiency Survey distributed to participating laboratories by the Molecular Pathology Committee of the College of American Pathologisis from 1998 through 2003 were analyzed. Results. - Thirty-nine proficiency survey specimens (29 positive and 10 negative for clonal IGH rearrangements) were distributed. For Southern blot analysis, 944 results were reported, with a successful response rate of 95%. For PCR detection, 2349 results were reported, with a successful response rate of 72%. A higher rate of successful responses by PCR was achieved using framework 3 primers in combination with other frameworks (82%) compared with framework 3 primers only (76%) and when fresh/ frozen (72%) compared with paraffin-embedded (65%) tissues were analyzed. Conclusions. - The performance of the participating laboratories was very good, by both Southern blot and PCR analysis. As expected, Southern blot analysis consistently detects a higher proportion of IGH rearrangements than PCR analysis. Further improvement and standardization of the IGH PCR assay is important if it is to replace Southern blot analysis as the standard method. Participation in this survey is a valuable tool for assessing laboratory performance and it directs our attention to areas where we may improve laboratory practice.