Quality improvement Initiative to eliminate silver precipitate during Periodic Acid Silver Methenamine Stain (PAMS) automated protocol of renal biopsies at McGill University Health Centre
Bibliographic record
Abstract
Abstract Introduction/Objective Annually, about 400 renal biopsies are processed at the McGill University Health Centre (MUHC) pathology laboratory located in Montreal, Canada. One of the stains used to visualize the glomerular basement membrane is Periodic Acid Silver Methenamine Stain (PAMS). In August 2020, a strong, granular precipitate of silver was noted during PAMS automated staining resulting in uninterpretable results and delay in the diagnosis. Based on a sample analysis, this problem affected 21 % of kidney biopsies. Methods/Case Report A cause-and-effect workflow was developed for systematic assessment of potential causes of the granular precipitate including pre-analytical and analytical factors. Some of the pre-analytical factors included length of time spent in transport before fixation and patient factors that predisposed precipitate formation. Analytical factors were categorized as fixation problems (temperature, pH, duration), embedding problems (parafilm temperature, cooling method, type of parafilm), slide preparation (temperature, water bath pH, dehydration and further processing steps), microtone parameters (microtone calibration, thickness, laboratory technologist expertise), automatic staining parameters (cartridge age, hematoxylin counterstain duration, wash-out period etc.) and coverslip placement (adhesive type, temperature, drying). Results (if a Case Study enter NA) Following our systematic approach, the cause of granular precipitate was identified as the timing of hematoxylin counterstain. A portion of renal biopsy tissue was taken from parafilm blocks of previouslly reported cases of patients with membranous glomerulonephritis to further test the hypothesis by introduction of various incubation times with the hematoxylin counterstain. Conclusion Best PAMS staining was attained when no hematoxylin counterstain was employed (instead, neutral red counterstain for 70 seconds was used). PAMS staining with hematoxylin counter stain for no more than 60 seconds was found to be acceptable for the interpretation of glomerular pathology.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.026 | 0.020 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.004 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".