Wadsworth Center

APPENDIX A

INTERPRETATION OF CONFIRMATORY/SUPPLEMENTAL TEST RESULTS

HEPATITIS B SURFACE ANTIGEN (HBsAg) CONFIRMATION

Confirmation of the presence of hepatitis B surface antigen on plasma is performed with a neutralization assay. Reduction of the specific radioactive count as compared to the control reaction, or "neutralization" by addition of specific antibodies to HBsAg, is evidence for specificity.

The results of the neutralization test are interpreted as follows:

> 50% reduction of the count rate - POSITIVE

< 50% reduction of the count rate - NEGATIVE

SYPHILIS CONFIRMATORY TESTING

TABLE A-1

INTERPRETATION OF SYPHILIS TEST RESULTS USING PK-TP SCREENING

PK-TP SCREENING
TEST RESULT 		RPR
RESULT		 FTA-ABS
RESULT		 INTERPRETATION
Non-reactive N/A N/A Negative
Repeatedly reactive Non-reactive Non-reactive Negative.
False positive screen.
Repeatedly reactive Reactive Reactive Positive syphilis serology.
Suggests current infection.
Repeatedly reactive Reactive Non-reactive Equivocal syphilis serology.
Requires medical evaluation.
Repeatedly reactive Non-reactive Reactive Positive syphilis serology.
Suggests past infection.

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