Quality assurance of immunodiagnostic tests in Australasia

A Royal College of Pathologists of Australasia (RCPA) sponsored Quality Assurance Program (QAP) in Clinical Immunology, involving 128 laboratories over a 1 yr period, revealed the following: successful participation in the program by 16 overseas laboratories (distant from Australia); only 30% of laboratories succeeded in returning their results by the scheduled date on every occasion; quantitation of urinary total protein and Bence Jones protein was poor and varied over a log scale; immunofixation was more successful in characterizing urinary paraprotein than immunoelectrophoresis; densitometry of protein electrophoresis appeared the method of choice in quantitating serum paraproteins accurately; nephelometric techniques gave better concordance between laboratories than turbidometric, radial immunodiffusion or agglutination techniques; poor concordance between laboratories in detecting weakly positive antinuclear antibodies (ANA); some laboratories had difficulties in identifying ANA patterns (only 60% of laboratories correctly identified the anticentromere pattern); few laboratories could correctly identify antibodies to extractable nuclear antigens (ENA); flow cytometry gave a smaller dispersion of lymphocyte subpopulation percentages than microscopy. A method was established to rank laboratory performance of selected tests over the 1 yr period. Such a comparative ranking scheme may alert laboratories in identifying specific or generalized deficiencies in performance.