❗ Exercise: In the clinical laboratory diagnostics department, during the morning shift, the internal quality control for the bilirubin parameter fails when the biochemical analyzer is started. The control sample consistently shows low total bilirubin values, while other biochemical parameters are normal. Restarting the analyzer and recalibration did not yield results. Cuvettes and reagents have been checked and replaced, control materials are within their shelf life, and the temperature regime is normal. The analyzer operates on a photometric principle. A similar pattern is observed in the next sample – a decrease in photometric readings in the short-wavelength range.
Question: What is the most likely cause of the system failure?
A) Contamination of the sample probe B) Error in the preparation of control material C) Defect in the analyzer lamp D) Insufficient sample mixing E) High humidity in the room
