BACKGROUND: We describe the analytical validation of an assay panel intended to assist clinicians with the diagnosis of systemic lupus erythematosus (SLE). The multi-analyte panel includes quantitative assessment of complement activation and measurement of autoantibodies. METHODS: The levels of the complement split product C4d bound to erythrocytes (EC4d) and B-lymphocytes (BC4d) (expressed as mean fluorescence intensity [MFI]) are measured by quantitative flow cytometry, while autoantibodies (inclusive of antinuclear and anti-double stranded DNA antibodies) are determined by immunoassays. Results of the multi-analyte panel are reported as positive or negative based on a 2-tiered index score. Post-phlebotomy stability of EC4d and BC4d in EDTA-anticoagulated blood is determined using specimens collected from patients with SLE and normal donors. Three-level C4 coated positive beads are run daily as controls. Analytical validity is reported using intra-day and inter-day coefficient of variation (CV). RESULTS: EC4d and BC4d are stable for 2days at ambient temperature and for 4days at 4°C post-phlebotomy. Median intra-day and inter-day CV range from 2.9% to 7.8% (n=30) and 7.3% to 12.4% (n=66), respectively. The 2-tiered index score is reproducible over 4 consecutive daysupon storage of blood at 4°C. A total of 2,888 three-level quality control data were collected from 6 flow cytometers with an overall failure rate below 3%. Median EC4d level is 6 net MFI (Interquartile [IQ] range 4-9 net MFI) and median BC4d is 18 net MFI (IQ range 13-27 net MFI) among 86,852 specimens submitted for testing. The incidence of 2-tiered positive test results is 13.4%. CONCLUSION: We have established the analytical validity of a multi-analyte assay panel for SLE.
BACKGROUND: We describe the analytical validation of an assay panel intended to assist clinicians with the diagnosis of systemic lupus erythematosus (SLE). The multi-analyte panel includes quantitative assessment of complement activation and measurement of autoantibodies. METHODS: The levels of the complement split product C4d bound to erythrocytes (EC4d) and B-lymphocytes (BC4d) (expressed as mean fluorescence intensity [MFI]) are measured by quantitative flow cytometry, while autoantibodies (inclusive of antinuclear and anti-double stranded DNA antibodies) are determined by immunoassays. Results of the multi-analyte panel are reported as positive or negative based on a 2-tiered index score. Post-phlebotomy stability of EC4d and BC4d in EDTA-anticoagulated blood is determined using specimens collected from patients with SLE and normal donors. Three-level C4 coated positive beads are run daily as controls. Analytical validity is reported using intra-day and inter-day coefficient of variation (CV). RESULTS: EC4d and BC4d are stable for 2days at ambient temperature and for 4days at 4°C post-phlebotomy. Median intra-day and inter-day CV range from 2.9% to 7.8% (n=30) and 7.3% to 12.4% (n=66), respectively. The 2-tiered index score is reproducible over 4 consecutive daysupon storage of blood at 4°C. A total of 2,888 three-level quality control data were collected from 6 flow cytometers with an overall failure rate below 3%. Median EC4d level is 6 net MFI (Interquartile [IQ] range 4-9 net MFI) and median BC4d is 18 net MFI (IQ range 13-27 net MFI) among 86,852 specimens submitted for testing. The incidence of 2-tiered positive test results is 13.4%. CONCLUSION: We have established the analytical validity of a multi-analyte assay panel for SLE.
Authors: Georgene W Hergenroeder; John B Redell; H Alex Choi; Lisa Schmitt; William Donovan; Gerard E Francisco; Karl Schmitt; Anthony N Moore; Pramod K Dash Journal: J Neurotrauma Date: 2018-07-05 Impact factor: 5.269
Authors: Rosalind Ramsey-Goldman; Roberta Vezza Alexander; Elena M Massarotti; Daniel J Wallace; Sonali Narain; Cristina Arriens; Christopher E Collins; Amit Saxena; Chaim Putterman; Kenneth C Kalunian; Tyler O'Malley; Thierry Dervieux; Arthur Weinstein Journal: Arthritis Rheumatol Date: 2019-11-25 Impact factor: 10.995
Authors: Joan T Merrill; Michelle A Petri; Jill Buyon; Rosalind Ramsey-Goldman; Kenneth Kalunian; Chaim Putterman; John Conklin; Richard A Furie; Thierry Dervieux Journal: Lupus Sci Med Date: 2018-05-23
Authors: Cristina Arriens; Roberta Vezza Alexander; Sonali Narain; Amit Saxena; Christopher E Collins; Daniel J Wallace; Elena Massarotti; John Conklin; Kenneth C Kalunian; Chaim Putterman; Rosalind Ramsey-Goldman; Jill P Buyon; Anca Askanase; Richard A Furie; Judith A James; Ghalib A Bello; Susan Manzi; Joseph Ahearn; Tyler O'Malley; Arthur Weinstein; Thierry Dervieux Journal: Lupus Sci Med Date: 2020-04