Antibodies to Nuclear and Related Antigens EQA
| Accreditation Status: | UKAS Schedule of Accreditation |
| Date Scheme started: | 1987, reconfigured 2002 |
| Clinical Applicability: | Diagnosis of autoimmune disease |
| Analytes: |
Nuclear Antibodies (ANA/DNA/ENA) (SER/005) Nuclear Antibodies (ANA/DNA) (SER/003) Qualitative identification of antibody to nuclear antigens (ANA), dsDNA and to the saline-extractable nuclear antigens (ENAs) SSA(Ro), SSB(La), Sm, RNP, Sm/RNP, Scl70, Jo-1, ENA screen, histones, nucleosomes, Chromatin and the pattern of antinuclear staining on immunofluorescence (IIF) in the HEp-2 cell system including the identification of centromere antibody. For the IIF pattern the ICAP classification is followed. The sample analytes included will depend on their prevalence in the general population, therefore not all analytes may be covered during the year. |
| Units for Reporting: |
Qualitative and quantitative responses for the ANA, dsDNA, Centromere and ENA, Histones, Nucleosomes and Chromatin antibodies in relation to relevant reference preparations. ANA: Titre, index or ratio dsDNA: IU/mL or titre Centromere: Titre or U/mL ENA’s: Ratio, index, U/mL or titre |
| Samples Distributed: | Liquid format. Normal and pathological human serum |
| Number of Distributions per year: | 6 |
| Number of Samples per Distribution: | 2 |
| Frequency of Distributions: | Every two months as outlined in the Distribution Schedule |
| Schedule of Analysis: | Data entry is via the web for the submission of results. Data analysis is commenced 21 days after sample dispatch. Late returns are accepted and will contribute to the laboratory's cumulative performance statistics. |
| Data Analysis: |
Qualitative responses are assessed in terms of MI scoring for each antibody specificity in relation to the Designated Response. Laboratories also submit the immunofluorescent staining pattern of antinuclear antibody. Reports show method or kit related statistics in terms of Method Laboratory Trimmed Mean (MLTM) and range of results reported. |
| Performance Scoring: | MI Scoring |
| Criteria of Performance: |
Laboratory performance for each antibody specificity is classified in terms of MI scoring over a running analytical window of 6 Distributions (12 months) The categories of performance are: Total MIS Good Zero Adequate 1-3 Poor >3 A OMIS of 3 or more for any one analyte will be classed as poor performance. |
| Persistent Poor Performance: | Defined as being in the Poor Performance category for two or more successive Distributions |