MASSCHECK® DRIED BLOOD SPOT CONTROL LEVEL I

Description of Event or Problem

IN THE FOLLOWING WE DESCRIBE THE ISSUE REGARDING THE MASSCHECK® DRIED BLOOD SPOT CONTROL LEVEL I (WITH UDI: (B)(4), (ORDER NO. (B)(4), WHICH ITSELF IS PART OF TO THE MASSCHECK® DRIED BLOOD SPOT CONTROL BI-LEVEL (I+II) (ORDER NO. (B)(4). WE FOUND THAT THE TARGET CONCENTRATION OF PHENYLALANINE INDICATED IN THE LEAFLET, DETERMINED USING THE NON-DERIVATISED METHODS 57000, 57000/F, 57111 AND 57111/F IS TOO HIGH FOR DRIED BLOOD SPOT CONTROL LEVEL I (ORDER NO. (B)(4). THE CONTROLS ARE PRIMARILY USED TO VERIFY THE ACCURACY AND PRECISION OF THE ANALYTICAL PROCEDURE. IF THE MEASURED VALUES ARE OUTSIDE THE RANGES SPECIFIED ON THE CONTROL PACKAGE INSERT, THE MEASUREMENT SYSTEM, THE SAMPLE PREPARATION PROCEDURE AND THE CALCULATION OF THE ANALYSIS VALUES MUST BE CHECKED. THIS MAY RESULT IN A DELAY OR FAILURE TO TRANSMIT SCREENING RESULTS. FURTHERMORE, THE CONTROLS CAN BE USED TO INTRODUCE OR ADJUST A FACTORISATION (RELATIVE RESPONSE FACTOR, RRF). THIS IS USUALLY USED TO HARMONISE MEASURED VALUES ON DEVICES OVER TIME AND ON DIFFERENT DEVICES AND TO ENABLE THE USE OF A UNIFORM CUT-OFF VALUE. FACTORING IN INCORRECT VALUES ADJUSTS NOT ONLY THE CONTROLS BUT ALSO ALL PATIENT SAMPLES BY THE SAME FACTOR. SINCE THE CUT-OFF VALUE IS NOT ADJUSTED ACCORDINGLY, THERE IS A RISK THAT METABOLIC DISORDERS WILL NOT BE DETECTED IN NEWBORN SCREENING DUE TO INCORRECT FACTORING. IN THE SCENARIOS DESCRIBED, PATIENTS WITH A DISEASE FOR WHICH PHENYLALANINE IS USED AS A MARKER IN NEWBORN SCREENING CAN LEAD TO A CRITICAL CONDITION WITH SERIOUS HEALTH CONSEQUENCES IF THE METABOLIC DISEASE IS NOT DETECTED OR NOT DETECTED IN TIME.