Impact of multi-dye multiplex technology on testing algorithm

Transcription

1 Impact of multi-dye multiplex technology on testing algorithm Lydia Blanco. Mª Isabel Gonzalez-Fraile Centro de Hemoterapia y Hemodonación de Castilla y León, España

2 TTI EPIDEMIOLOGICAL DATA IN SPAIN

3 NAT YIELD IN SPAIN Donations NAT + WP NAT YIELD Serology - HCV 10, / 614,925 HIV 10, / 347,948 HBV 9, * 51 1/ 187,688 * 459 OBI NAT yield 1/20,854 Grupo de serología SETS NAT YIELD IN CASTILLA Y LEÓN Donations NAT+ WP NAT YIELD Serology - HCV 611, / 305,769 HIV 611, / 611,538 HBV 611, * 2 1/ 305,769 * 21 OBI NAT yield 1/29,120

4 The most important risk for transmission is for HBV, nevertheless only 5% of infected individuals become chronic carriers OBI rate in Spain is approx. 1/ 21,000 donations, and we can consider that 3% (or more?) of the recipients can become infected HIV still continues to be a menace for transfusion safety and in Spain the risk is increasing in MSM as in other countries Post transfusion HCV infection is not very frequent in our country

5 TESTS FOR TTI IN OUR LABORATORY Serology : Abbott Prism/Architect NAT: : Roche cobas s 201/MPX v1.0, MP : Roche cobas s 201/MPX v2.0, MP6

6 DECISION ALGORITHMS IN SEROLOGICAL TESTS AND NAT TESTS

7 The decision algorithm for initial/repeated reactive results in serology related to confirmatory tests, deferral or acceptance of donors and donations, look back.. is clearly defined in the Spanish regulations

8 SEROLOGY TESTING ALGORITHM NEGATIVE RESULT SEROLOGY (ABBOTT PRISM) POSITIVE RESULT DONOR ACCEPTANCE (if NAT is non-reactive) NEGATIVE RESULT REPEAT IN DUPLICATE (SAME TECHNIQUE, SAME SAMPLE) 1 OR 2 POSITIVE RESULTS CONFIRMATORY TEST (NEUTRALIZATION, WB,INNOLIA) DISCARD DONATION CALL BACK THE DONOR REPEAT TESTS WITH NEW SAMPLE

9 DECISION ALGORITHM FOR POSITIVE RESULTS IN SEROLOGY NEGATIVE CONFIRMATORY TEST POSITIVE OR INDETERMINATE DONOR ACCEPTANCE INFO TO HOSPITALS PLASMA INDUSTRY POSITIVE INDETERMINATE DEFINITIVE DEFERRAL LOOK BACK OF PREVIOUS DONATIONS TEMPORARY DEFERRAL DONOR FOLLOW UP

10 However, this is not the rule for NAT algorithms, and, in fact, we can find some difficult situations. A misleading interpretation of data can lead us to defer healthy donors or to accept potentially infectious units

11 GENERAL NAT DECISION ALGORITHM NAT HBV, HCV, HIV NEGATIVE POSITIVE DONOR ACCEPTANCE DISCARD DONATION DONOR TEMPORARY DEFERRAL NEW SAMPLE NEGATIVE POSITIVE DEFINITIVE DEFERRAL INFO TO HOSPITALS TRACE BACK /LOOK BACK

12 NAT ALGORITHM FOR POSITIVE RESULTS MPX v1.0 (MP6) REPEAT INDIVIDUAL TEST NAT POSITIVE POOL IDENTIFICATION OF REACTIVE SAMPLE HIV CONFIRMATION Serology, different NAT HCV CONFIRMATION Serology, different NAT HBV CONFIRMATION Serology, different NAT POSITIVE: HIV INFECTION NEGATIVE POSITIVE: HCV INFECTION NEGATIVE POSITIVE and HBsAg POSITIVE: HBV INFECTION POSITIVE and HBsAg NEGATIVE: WP or OBI??? NEGATIVE: OBI???

13 NAT ALGORITHM : Pool testing MPX v1.0 Pool reactive, individual donations non-reactive initial reactive (false reactive pool) Pool reactive, individual donation reactive, viral target not identified repeat reactive, true positive pool and donation, unresolved

14 PROBLEMS WITH MPX v1.0 The results are delayed. After the identification of the initially reactive specimen we need a specific NAT test for each virus The donation is discarded and we call back the donor for a new sample without an initial diagnosis Our alternative laboratory uses for HBV a quantitative test, COBAS AmpliPrep/COBAS TaqMan HBV test v2.0 whose sensitivity is 20 IU/mL (sensitivity for MPX v1.0 is 3 IU/mL) problem with OBI

15 NAT DECISION ALGORITHM FOR POSITIVE RESULTS MPX 2.0 (MP6) NAT POSITIVE POOL REPEAT INDIVIDUAL TEST HIV POSITIVE: HIV infection HCV POSITIVE: HCV infection HBV POSITIVE HCV,HIV,HBV NEGATIVE FALSE POSITIVE HBsAg POSITIVE : HBV INFECTION HBsAg NEGATIVE : WP or OBI

16 NAT ALGORITHM : Pool testing MPX v2.0 Pool reactive, individual donations non-reactive initial reactive (false reactive pool) Pool reactive, individual donation reactive, viral target identified repeat reactive (true positive pool and donation)

17 ADVANTAGES with MPX v2.0 If some of the individual sample result is positive result is obtained in less than 24h We can call back the donor with a previous diagnosis We avoid the problem of alternative NAT tests with different (sometimes less) sensitivity for HBV

18 COMPARISON OF NAT RESULTS FOR MPX V1, and MPX V2 Year MPX v1 Donations IR pool/total no. pools tested (%) False positive pools (%)* ,606 21/13,411 (0,15%) 15/13,411 (0.11%) ,831 10/15,557 (0.06%) 5/15,557 (0.03%) ,462 12/18,158 (0.06%) 9/18,159 (0.05%) ,082 8/13,922 (0.05%) 7/13,922 (0.05%) Year MPX v2 Donations IR pool/total no. pools tested (%) False positive pools (%)* ,729 2/4,214 (0.04%) 1/4,214 (0.02%) ,460 18/17,434 (0.10%) 17/17,434 (0.10%) *All ID samples of false positive pools were negative

19 NAT YIELD FOR MPX V1 AND MPX V2 MPX v1 DONATIONS HIV HCV HBV OBI TOTAL MPX v2 DONATIONS HIV HCV HBV OBI , , TOTAL 127,

20 THE IMPORTANCE OF OBI IN OUR REGION

21 OBI IN DONORS Donors ID PCR Anti-HBc HBs Ag Anti-HBs In 2011 ( MPX 1.0) we studied 18 samples pool positive, ID positive and HIV, HCV negative and HBV negative (?) (cobas taqman) 13 men 2 women Mean age: 55 years All of them were anti-hbc positive UI/L ? IU/L IU/L IU/L * SEROLOGY: 14 POSITIVE IU/L IU/L IU/L

22 Sample no. Genotype Titer 1 D < 6 IU/mL 2 Target not detected 3 < 6 IU/mL 4 < 6 IU/mL 5 D < 6 IU/mL We can asses the OBI diagnostic in 17/18 cases 6 D Target not detected 7 D < 6 IU/mL 8 D < 6 IU/mL 9 D < 6 IU/mL 10 D < 6 IU/mL 11 < 6 IU/mL 12 D <10 UI/ml 13 A2 14 A2 <10 UI/ml 15 A2 <10UI/ml 16 D 17 D <10UI/ml 18 A2 Target not detected

23 TRACEBACK OBI DONORS Donor Number previous donations Anti-HBc in previous donations HBV PCR in previous donations NA NA NEGATIVE NA NA NEGATIVE NEGATIVE NEGATIVE NEGATIVE NEGATIVE NEGATIVE 12 3 NEGATIVE NEGATIVE NA NEGATIVE NA NEGATIVE NA NEGATIVE 17 8 NA NEGATIVE 18 1 NA NEGATIVE

24 LOOK BACK OF RECIPIENTS NUMBER OF RECIPIENTS DEATHS SAMPLES OBTAINED RCC FFP MB FFP FRACTIONATION 63??? PC TOTAL * 23 * NO EVIDENCE OF HBV INFECTION

25 LOOK BACK OF RECIPIENTS Number of recipients HBV PCR HBs Ag Anti-HBc* Anti-HBs POS POS POS POS - 1 POS (ID) - POS - 5/23 OBIs, (22%) are they infectious???? * anti-hbc in Spain aprox. 15%

26 CONCLUSIONS Main problem with NAT testing is samples with low viral loads which are only detected some of the time: Most likely cause is OBI Different algorithms designed to determine true status of sample Prevent TTI Prevent loss of donation/donor Optimum test algorithm which also fits in with lab workflow Look-back, trace-back important

27 THANK YOU!!!!! Acueducto de Segovia Aprox. year 50 AC