inforMED
MalfunctionMZP

KIT COBAS 58/68/8800 MPX 480T US

Received Dec 23, 2025 · Event occurred Sep 25, 2025

Report 2243471-2025-05316 · MDR key 23877104

Device

Generic name

Assay, Hybridization And/or Nucleic Acid Amplification For Detection Of Hepatiti

Catalog number

09040854190

Lot number

N01895

Product problems

  • False Negative Result
  • False Negative Result

Patient

NA · Unknown

  • No Clinical Signs, Symptoms or Conditions
  • No Clinical Signs, Symptoms or Conditions

Narrative

Additional Manufacturer Narrative

THE COBAS 8800 SERIAL NUMBER WAS (B)(6). THE INVESTIGATION INDICATED NO PRODUCT-RELATED ISSUES WERE IDENTIFIED. THE PRIMARY CAUSAL FACTOR FOR THE INITIAL FALSE NON-REACTIVE RESULT IS THE LOW VIRAL LOAD OF THE SAMPLE COMBINED WITH THE DILUTION EFFECT OF THE POOLING PROCEDURE. THE SAMPLE WAS TESTED IN A POOL OF SIX (PP6), WHICH APPLIED A SIGNIFICANT DILUTION FACTOR TO THE ALREADY LOW CONCENTRATION OF HIV TARGET. THE DILUTION PUSHED THE VIRAL LOAD CONCENTRATION BELOW THE ASSAY'S LOD FOR THE POOLED SAMPLE, RESULTING IN A FALSE NON-REACTIVE READING.

Description of Event or Problem

THERE WAS AN ALLEGATION OF DISCREPANT HIV RESULTS WITH THE COBAS®MPX KIT (480T) FROM THE COBAS 8800 ANALYZER FOR A SINGLE PATIENT. ON 25-SEP-2025, THE INITIAL PP6 SAMPLE GENERATED A HIV NON-REACTIVE RESULT. REPEAT ON ALINITY GENERATED REACTIVE RESULTS. 23-OCT-2025, THE SAME SAMPLE WAS REPEATED ON ANOTHER 8800 INSTRUMENT AND GENERATED AN HIV REACTIVE RESULT. THE SAME SAMPLE WAS REPEATED THE NEXT DAY AND GENERATED A NON-REACTIVE RESULT FOR HIV AND HCV AND A REACTIVE RESULT FOR HBV WITH CT 36.47. SEROLOGY TESTING WAS PERFORMED WITH ADVIA, WHICH GENERATED A BORDERLINE POSITIVE RESULT, AND ARCHITECT, WHICH GENERATED A NEGATIVE RESULT.