Results; Limitations Of The Assay - Axis-Shield RPR Bedienungsanleitung

Negative Control and Positive Control reagents can be used for quality control purposes. Use controls
(instead of samples) and follow the procedure described above for the qualitative test.
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Results

Read the results immediately after the 8 minutes rotation. Read with the naked eye, preferably in good
daylight.
A negative reaction will appear as a concentration of smooth carbon in the center of the circle or as a
smooth, even gray suspension throughout the test circle.
A weak positive reaction is characterized by a concentration of fine black aggregates surrounded by
a diffuse area of fine black aggregates.
A positive reaction is the production of black aggregates most commonly observed throughout the
test circle.
The last circle in the dilution series that contains any black aggregates gives the titer of the sample.
negative
weak positive
A nonreactive result indicates that the sample tested either does not contain antibodies against VDRL
antigen or that it contains antibodies against VDRL antigen at concentrations below the detectable
limits of Axis-Shield RPR.
A reactive result indicates that the sample tested either contains anti-VDRL or contains a
nonspecifically reacting factor. Specimens that initially show a reactive result may be retested. If the
specimen is reactive after retest, a specimen is considered positive for anti-VDRL, which is a
presumptive diagnosis for syphilis.
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Limitations of the assay

Occasionally biologically false positive reactions (BFP's) can occur with Axis-Shield RPR, as with all
other reagin tests. These results can be caused by a variety of diseases including infectious
mononucleosis, leprosy, lupus erythematosus, malaria, vaccinia and viral pneumonia.
For confirmation a treponemal test such as Trepanostika TP recombinant, FTA-ABS or TPHA, should
be performed on all positive reagin tests.
Cases of zone phenomena have been observed. Consequently, a negative qualitative test for a
patient strongly suspected of having syphilis must be confirmed by a quantitative test, in order to
eliminate the possibility of a zone phenomenon.
Qualitative test
Semi-quantitative test
negative
positive
Interpretation of results
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