The case involves a 35-year-old pregnant woman at 38 weeks' gestation with gestational hypertension who was ordered for a 24-hour urine protein quantification because of elevated blood pressure and abnormal protein findings. The laboratory reported a result of 547.87 g/24 h, which the attending physician considered inconsistent with her clinical condition. The cause of the error was a technical fault – the "F" alarm code (signaling that the measurement range was exceeded) got into the laboratory information system and disrupted the automatic conversion of units. Instead of the correct procedure, which would have required increasing the dilution ratio and re-measuring, the alarm code was manually suppressed in the system. This led to a 100-fold overestimation of the result because the data was erroneously reported in "g/l" units instead of "mg/dL". The case highlights the critical risk associated with the failure of unit uniformity between detection platforms and information systems in clinical laboratories. It emphasizes the importance of following standard procedures when error codes occur and the need for quality management in laboratories to avoid adverse clinical outcomes.