Treponema pallidum (RPR) with Reflex to Titer and TP-PA
Specimens will be screened by an RPR test that uses charcoal agglutination for detection of reagin antibodies. Reagin antibodies are non-treponemal antibodies produced by the body's defense mechanism in response to an infection with Treponema pallidum. If the RPR is reactive, a quantitative titer and a TP-PA will be done. The TP-PA test is a confirmatory treponemal pallidum particle agglutination test. If latent syphilis is suspected and noted on request form, a TP-PA will be performed even if the RPR is non-reactive.
Charcoal Agglutination/Particle Agglutination
One 6 mL red top vacutainer tube
2 mL of whole blood or 1 mL of serum at 2-8° C
Store specimens at refrigerator temperature (2-8° C) prior to shipment.
Specimens should be sent daily or next working day.
Transport in MSPHL shipping containers at room temperature.
Acceptable Specimen Type(s)
Test Request Form(s)
RPR Titer: < 1:1
No Name on Specimen
Name on Specimen Does Not Match Name on Request Form
Quantity Not Sufficient
In Transit for More Than 10 Days
Hemolysis, lipemia, and bacterial contamination
1 day after specimen receipt
86592 RPR; if reflexed, add 86593 RPR titer and 86780 TP-PA
RPR Titer: 31147-2
Biological false positive reactions occur occasionally with the carbon antigen (RPR) from individuals with a history of drug abuse, or with diseases such as lupus erythematosus, malaria, vaccinia, mononucleosis, leprosy, viral pneumonia, and after smallpox vaccinations. Pinta, yaws, bejel, and other treponemal diseases produce positive reactions in this test. A final diagnosis should not be made on the result of a single test, but should be based on a correlation of test results with other clinical findings.