COMMON SPECIFICATIONS FOR DEVICES INTENDED FOR DETECTION OR QUANTIFICATION OF MARKERS OF HUMAN T-CELL LYMPHOTROPIC VIRUS (HTLV) INFECTION
ANNEX IVSupplementary provisions
ANNEX IV COMMON SPECIFICATIONS FOR DEVICES INTENDED FOR DETECTION OR QUANTIFICATION OF MARKERS OF HUMAN T-CELL LYMPHOTROPIC VIRUS (HTLV) INFECTION Scope This Annex applies to devices intended for detection or quantification of markers of human T-cell lymphotropic virus (HTLV) infection. Table 1 applies to first-line assays for antibodies against HTLV I or II (anti-HTLV I/II) which are not rapid tests. Table 2 applies to first-line assays for anti-HTLV I/II which are rapid tests. Table 3 applies to confirmatory assays for anti-HTLV I/II. Table 4 applies to NAT devices for HTLV I/II. Table 1. First-line assays: anti-HTLV I/II Performance characteristic Specimen Specimen numbers, features, use Acceptance criteria Diagnostic sensitivity Positive specimens ≥300 HTLV-I ≥100 HTLV-II including 25 positive ‘same day’ fresh serum specimens (≤ 1 day after specimen taking) all true positive specimens shall be identified as positive Seroconversion panels To be defined when available diagnostic sensitivity during seroconversion shall represent the state of the art, if applicable Diagnostic specificity Unselected blood donors (including first-time donors) ( 1 ) ≥5 000 ≥ 99,5% Hospitalised patients ≥200 Potential limitations for specificity, if any, shall be identified Cross-reactivity Potentially cross-reacting specimens ≥100 in total (e.g. RF+, from related virus infections, from pregnant women) Table 2. Rapid tests: anti-HTLV I/II Performance characteristic Specimen Specimen numbers, features, use Acceptance criteria Diagnostic sensitivity Positive specimens ≥300 HTLV-I ≥100 HTLV-II all true positive specimens shall be identified as positive Seroconversion panels To be defined when available diagnostic sensitivity during seroconversion shall represent the state of the art, if applicable Diagnostic specificity Unselected blood donors (including first-time donors) ≥1 000 ≥ 99% Hospitalised patients ≥200 Potential limitations for specificity, if any, shall be identified Cross-reactivity Potentially cross-reacting specimens ≥200 specimens from pregnant women ≥100 other potentially cross-reacting specimens in total (e.g. RF+, from related infections) Table 3. Confirmatory assays: anti-HTLV I/II Performance characteristic Specimen Specimen numbers, features, use Acceptance criteria Diagnostic sensitivity Positive specimens ≥200 HTLV I ≥100 HTLV II Identification as “confirmed positive” or “indeterminate”, not as “negative” Seroconversion panels To be defined when available diagnostic sensitivity during seroconversion shall represent the state of the art, if applicable Diagnostic specificity Blood donors ≥200 No false positive results Hospitalised patients ≥200 Cross-reactivity Potentially cross-reacting specimens ≥50 in total (including specimens from pregnant women, specimens with indeterminate results in other confirmatory assays) Table 4. NAT devices for HTLV I/II 1. For target sequence amplification devices, a functionality control for each specimen (internal control) shall reflect the state of the art. This control shall as far as possible be used throughout the whole process, i.e. extraction, amplification/hybridisation, detection. 2. Genotype and/or subtype detection shall be demonstrated by appropriate primer or probe design validation and shall also be validated by testing characterised genotyped specimens. 3. Potential cross-reactivity of non-target nucleic acid sequences shall be analysed by appropriate primer or probe design validation and shall also be validated by testing selected specimens. 4. Results of quantitative NAT devices shall be traceable to international standards or calibrated reference materials, if available, and be expressed in international units utilised in the specific field of application. Performance characteristic Specimen Specimen numbers, features, use Acceptance criteria Analytical sensitivity International reference preparations NAT sensitivity and NAT LOD shall be validated by dilution series of reference materials, testing of replicates (minimum 24) at different analyte concentrations, including those with transition from positive to negative results with the respective NAT device. LOD shall be expressed as 95% positive cut-off value (IU/ml) after statistical analysis (e.g. Probit). ( 2 ) quantitative NAT: definition of lower, upper quantification limit, precision, accuracy, ‘linear’ measuring range, ‘dynamic range’. Reproducibility at different concentration levels According to the state of the art HTLV I and HTLV II genotype sensitivity all relevant genotypes, preferably from international reference materials potential substitutes for rare HTLV genotypes (to be quantified by appropriate methods): cell culture supernatants; in vitro transcripts; plasmids Qualitative NAT: at least 10 specimens/genotype or subtype Quantitative NAT: dilution series for demonstration of quantification efficiencies According to the state of the art Diagnostic specificity Blood donor specimens Qualitative NAT: ≥500 Quantitative NAT: ≥100 According to the state of the art Cross-reactivity Potentially cross-reacting specimens ≥10 human retrovirus positive specimens (e.g. HIV-1, HIV-2) According to the state of the art Carry-over High HTLV RNA positive; HTLV RNA negative At least five runs with alternating high-positive and negative specimens shall be performed during robustness studies. The virus titres of the high positive specimens shall be representative of high virus titres occurring naturally. According to the state of the art Detection in relation to antibody status HTLV-RNA positives: anti-HTLV negative, anti-HTLV positive Pre-seroconversion (anti-HTLV negative) and post-seroconversion (anti-HTLV positive) specimens According to the state of the art Whole system failure rate HTLV RNA low-positive ≥100 HTLV RNA low-positive specimens shall be tested. These specimens shall contain a virus concentration equivalent to three times the 95 % positive cut-off virus concentration. ≥99% positive ( 1 ) Blood donor populations shall be investigated from at least two blood donation centres and consist of consecutive blood donations, which have not been selected to exclude first-time donors. ( 2 ) Reference: European Pharmacopeia 9.0, 2.6.21 Nucleic acid amplification techniques, Validation.