Preanalytic errors in anatomic pathology: study of 10,574 cases from five Portuguese hospitals

Identification of errors in anatomic pathology is an important issue in medical practice. The main objective of this study was to determine the prevalence and characterize preanalytic errors in surgical pathology and cytology samples. We also intended to explore associations between error prevalence and procedures implemented in hospitals concerning the type of requisition forms, use of guidelines for case acceptance and existence of error notification system.

We analyzed 10,574 cases in five Portuguese hospitals. The pathology laboratories recorded during 20 days all cases submitted with preanalytic errors, using an input form that allowed the identification of sample type, error description, action taken before error, the professional who detected the fail and the test cycle segment where it was identified. Subsequently, particular procedures in use for preanalytic phase were characterized for each hospital.

The prevalence of cases with error was 3.1% (330/10,574), 95% confidence interval: 2.8%-3.5%. Errors occurred in 4.1% (250/6079) of histology specimens and 0.9% (40/4477) of cytology specimens, and included errors in the requisition forms (2.6% error rate) and in the sample container (1.5% error rate). Acceptance of cases with error was the most frequent action (66.9%), followed by rejection (24.4%) and retention (8.7%).

The existence of written norms for sample acceptance and error reporting systems to submitting services and patient safety department were proven to be associated to lower error prevalence.