Lab Inconsistency Creates Silent Quality Problem in Routine Cancer Diagnosis
An international study found that cancer samples prepared for microscopic analysis vary wildly in quality depending on which lab method is used—with failure rates ranging from 4% to 80%. The inconsistency threatens diagnostic accuracy and could force costly repeat procedures, signaling an urgent need for standardized preparation protocols across pathology labs.
Originaltitel: Cellularity of Routinely Prepared Cell Blocks: Insights From an International Study
ABSTRACT Objective Formalin‐fixed, paraffin‐embedded (FFPE) cell blocks (CBs) are widely used for processing cytology specimens, but preparation methods remain variable and non‐standardised. Low cellularity is a common limitation that may compromise diagnostic utility. This study aimed to evaluate the cellularity of routinely prepared CBs across different preparation methods, laboratories and sample types. Methods Each laboratory in this multicentre observational study retrospectively assessed 50 consecutive CBs prepared using a single method. Cellularity of Haematoxylin and Eosin (H&E)‐stained sections was semi‐quantitatively evaluated by two independent reviewers per laboratory in four categories: acellular, low (≤ 100 cells), medium (100–500 cells) and high cellular (> 500 cells). The proportion of poorly cellular CBs (acellular + low cellular) was compared across methods, laboratories and sample types using non‐parametric tests. Results Cellularity was assessed for 1817 CBs prepared using Agar (22%), HistoGel (19%), Plasma‐Thrombin (19%), Cellient (17%), In‐house (15%) and Shandon/Epredia (8%) methods. The proportion of poorly cellular CBs ranged from 4% to 80% across laboratories (mean 27%, median 25%), with no consistent clustering by method. Median proportions by method ranged from 12% (Cellient) to 35% (Agar), but inter‐method differences were not statistically significant ( p > 0.05). Substantial variability was observed both across and within sample types and preparation methods. Conclusions The study revealed marked variability in the proportion of poorly cellular CBs among preparation methods and laboratories, highlighting the need for improved processing and monitoring of CB adequacy.