Treponema pallidum particle agglutination (TP-PA)

TEST DESCRIPTION

Agglutination assay for detecting antibodies against Treponema pallidum in human serum or plasma as an aid in the diagnosis of syphilis. Treponema pallidum, the causative agent of syphilis, induces the production of at least two types of antibodies in human infection: anti-treponemal antibodies that can be detected by the TP-PA test and non-treponemal antibodies (reagin) that can be detected by the RPR test.

Methodology

Qualitative immunoassay

Reference range

Non-reactive

TEST FREQUENCY & RESULT AVAILABILITY

Performed twice weekly. Results are typically available within three business days after specimen receipt.

ACCEPTABLE SPECIMEN TYPES AND COLLECTION

• Serum: Collect ≥2 ml of venous blood in a serum separator tube (SST). 
• Plasma: Collect ≥2 ml of venous blood in an EDTA (lavender-top), lithium heparin (green-top), or citrate (light blue-top) tube. 
• Note: Centrifugation should be performed 30 minutes to 2 hours after collection.

SPECIMEN STORAGE

Spun (centrifuged) serum: store refrigerated (2–8 °C/36–46 °F) for up to 5 days.

Spun (centrifuged) plasma: store refrigerated (2–8 °C/36–46 °F) for up to 2 days.

Unspun (not centrifuged) serum or plasma: store at room temperature (15–25°C/59–77°F) for up to 2 hours.

SPECIMEN TRANSPORT

Shipping conditions should follow the temperature and time requirements outlined above. Refrigerated specimens should be transported on wet ice.

REJECTION CRITERIA

• Spun serum: holding time greater than 5 days refrigerated
• Spun plasma: holding time greater than 2 days refrigerated
• Non-spun tubes: holding time greater than 2 hours at room temperature
• Specimen container not labeled or not sealed properly
• Grossly contaminated, hemolyzed, lipemic, or icteric specimens should not be used

CODES

CPT: 86780
LOINC: 24312-1
Test code: 5065

TEST FEE

Refer to the current fee schedule.