Description of Event or Problem · 0
A GREATER THAN 22000 U/L CREATINE KINASE (CK) RESULT WAS REPORTED AS NON-DETECTABLE. THIS ERRONEOUS RESULT CAUSED DELAY OF CARE FOR A PEDIATRIC PATIENT WITH RHABDOMYOLYSIS. THE TEST WAS PERFORMED ON (B)(6)2024 ON A ROCHE PRO C503 ANALYZER. THE FIRST RESULT WAS GREATER THAN THE ANALYTICAL MEASUREMENT RANGE (AMR), SO AN AUTO DILUTION WAS TRIGGERED. THE DILUTED RESULT WAS STILL HIGHER THAN WHAT THE INSTRUMENT COULD MEASURE BUT FAILED TO TRIGGER THE CRR HIGH FLAG PER THE RULE BUILT IN THE SYSTEM. CRR STANDS FOR CLINICAL REPORTABLE RANGE, WHICH IS AMR MULTIPLIED BY THE DILUTION FACTOR. THE RESULT FROM THE INSTRUMENT READ AS 1.67 U/L AFTER DILUTION, SO IT WAS REPORTED OUT AS <7 U/L. A ROCHE TICKET WAS PLACED ON (B)(6)2024 AFTER INTERNAL INVESTIGATION, AND A ROCHE REPRESENTATIVE REACHED OUT TO US THE SAME DAY. THE FOLLOWING TWO EXPLANATIONS WERE PROPOSED: 1. THE CK ASSAY WORKS BY MEASURING ABSORBANCE AFTER A CERTAIN AMOUNT OF TIME ONCE A REACTION IS INITIATED. BECAUSE THERE WAS SO MUCH CK IN THIS SPECIMEN, THE REACTION OCCURRED FASTER THAN NORMAL. THE REACTION WAS OVER BY THE TIME THE INSTRUMENT NORMALLY MEASURES THE ABSORBANCE. OUR QUESTION TO ROCHE WAS WHY THE UNDILUTED SAMPLE DIDN'T CONSUME ALL REAGENT BEFORE THE MEASUREMENT TAKING PLACE. WE NEED TO UNDERSTAND WHY THE REAGENT WAS CONSUMED QUICKER AFTER THE SPECIMEN BEING DILUTED 11 TIMES. 2. THE DILUTION DID NOT HAPPEN. OUR QUESTION TO ROCHE WAS THE INSTRUMENT SHOWED AUTO DILUTION TAKING PLACE. THE READING FROM UNDILUTED SAMPLE WAS 6.45, AND DILUTED SAMPLE WAS 1.67. IF DILUTION DID NOT HAPPEN, WHY DID THE INSTRUMENT RUN THE SAMPLE TWICE AND SHOWED AUTO DILUTION INFORMATION?