Sensitivity of NAT blood screening assays in performance evaluation

and proficiency programs

Harry van Drimmelen, Nico Lelie, (VQC-Sanquin) and the principal investigators participating

in the multi-center studies and EQAS program

viral standards

proficiency panels reference panels run controls

inter-laboratory comparison validation of assays

VQC Concept external quality control program

Data sets included in probit analysis

• VQC proficiency program for NAT blood screening assays (n=2512)

• Validation studies for implementation of NAT assays in blood screening laboratories (n=11563)

Evaluation panels

• PeliCheck HIV-RNA genotype B*

• PeliCheck HCV-RNA genotype 1**

• VQC HCV-RNA proficiency panel *

• VQC HIV-RNA proficiency panel **

** Dilutions of the VQC HIV-RNA genotype B standard** Dilutions of the VQC HIV-RNA genotype B standard

* Dilutions of the VQC HCV-RNA genotype 1 standard* Dilutions of the VQC HCV-RNA genotype 1 standard

Performance of Procleix TMA laboratories on HCV-RNA panels (probit analysis)

0%

25%

50%

75%

100%

-2 -1 0 1 2 3 4

log (conc HCV-RNA)

% positive

Proficiency panels

PeliCheck panels

Potency 0.97 (0.48-2.07) nprof = 382, nvalidation = 719

Performance Nuclisens-Ampliscreen assay on HCV-RNA panels (probit analysis)

-25%

0%

25%

50%

75%

100%

-2 -1 0 1 2 3

log (conc HCV-RNA)

% positive

Proficiency panels

PeliCheck panels

Potency 1.11 (0.65-1.95) nprof = 107, nvalidation = 381

Detection limits on PeliCheck and proficiency panels in geq/ml

(as calculated by probit analysis; parallel lines)

AssayAssay Marker Proficiency Marker Proficiency PeliCheck PeliCheck 50 % 95 % 50 % 95 % 50 % 95 % 50 % 95 %

Nucl.-Ampl. HIVNucl.-Ampl. HIV 5.9 (4-9) 32 (20-62) 4.6 (3-6) 25 (16-47) 5.9 (4-9) 32 (20-62) 4.6 (3-6) 25 (16-47)

Nucl.-Ampl. HCVNucl.-Ampl. HCV 7.7 (5-12) 51 (32-90) 6.9 (5-9) 46 (32-75) 7.7 (5-12) 51 (32-90) 6.9 (5-9) 46 (32-75)

TMA duplexTMA duplex HIV HIV 5.6 (2-12) 46 (21-128) 4.0 (2-7) 33 (17-91) 5.6 (2-12) 46 (21-128) 4.0 (2-7) 33 (17-91)

TMA duplex HCV 10 (6-18) 94 (51-209) 11 (7-16) 96 (56-205)TMA duplex HCV 10 (6-18) 94 (51-209) 11 (7-16) 96 (56-205)

Ampliscreen HIVAmpliscreen HIV 11 (8-15)113 (77-184) 7 (4-10) 68 (42-127) 11 (8-15)113 (77-184) 7 (4-10) 68 (42-127)

Ampliscreen HCV 11 (8-14) 96 (68-152) 10 (6-15) 89 (53-169)Ampliscreen HCV 11 (8-14) 96 (68-152) 10 (6-15) 89 (53-169)

Roche Multiprep-Ampliscreen detection limits in geq/ml

Marker Marker 50 % 50 % 95 % 95 % n* n*HCV-RNA 10 (8-13) 95 (68-148) 471 HCV-RNA 10 (8-13) 95 (68-148) 471 HBV-DNA 8 (6-13) 100 (55-291) 158HBV-DNA 8 (6-13) 100 (55-291) 158HIV-RNA 9 (7-11) 102 (70-166) 480HIV-RNA 9 (7-11) 102 (70-166) 480

* Number VQC standard dilutions tested in * Number VQC standard dilutions tested in performance evaluation studies and proficiency programperformance evaluation studies and proficiency program

Conclusion and discussion

• The limiting dilution results on PeliCheck validation panels and proficiency panels are comparable

Performance Procleix TMA laboratories on HIV-RNA panels (probit analysis)

0%

25%

50%

75%

100%

-2 -1 0 1 2 3 4

log (conc HIV-RNA)

% positive

Proficiency panelsPeliCheck panels

Potency 1.41 (0.58-4.36) nprof = 366, nvalidation = 897

Performance Nuclisens-Ampliscreen assay on HIV-RNA panels (probit analysis)

0%

25%

50%

75%

100%

-2 -1 0 1 2 3

log (conc HIV-RNA)

% positive

Proficiency panels

PeliCheck panels

Potency 1.28 (0.76-2.29) nprof = 107, nvalidation = 168