Sign In
Labcorp Oklahoma, Inc.
Test Directory


Syphilis Antibody Screen

Order Name SYP AB
Test Number: 5500607
Revision Date 07/10/2024
Test Name Methodology LOINC Code
Syphilis Antibody Screen
Chemiluminescence Assay 24110-9 
Specimen Specimen Volume (min) Specimen Type Specimen Container Transport Environment
Preferred 3 mL (0.6 mL) Serum Clot Activator SST Refrigerated
Alternate 1 3 mL (0.6 mL) Plasma Lithium Heparin PST (Light Green Top) Refrigerated
Instructions Stability: Ambient 3 days. Refrigerated 7 days. Frozen 30 days.
Testing Schedule Mon - Sat 
Expected TAT 1-2 Days  
Clinical Use This screening assay tests for the presence of total antibody specific to Treponema pallidum. 

Interpretation for the Syphilis testing Algorithm
The clinical presentation, medical history and timing of the onset of a suspected Syphilis infection (median incubation period is 3 weeks but may vary from 3-90 days) are all vitally important in the interpretation of the Syphilis testing results. The initial test of the Syphilis Antibody Screen Algorithm is a Treponemal Antibody Assay (Syp Ab) and if positive (note index in footnote) the specimen is reflexed to the Non-Treponemal Antibody Assay (RPR). The Non-Treponemal Antibody Assay (RPR) will indicate the presence or absence of an active infection. However, due to abnormally high levels of activity which occurs in up to 2% of infected persons, especially in secondary Syphilis and pregnancy, the Non-Treponemal Antibody Assay (RPR) may give a false non-reactive result. Therefore, if the index of suspicion is high but testing is negative, please notify the laboratory and request the laboratory to rerun the Non-Treponemal Antibody Assay (RPR) at higher dilutions than originally performed. The Non-Treponemal Antibody Assay (RPR) should become nonreactive 1 year after successful therapy in primary Syphilis and 2 years in secondary Syphilis; most patients with late Syphilis will be nonreactive by the fifth year after successful therapy. The Non-Treponemal Antibody Assay (RPR) should decrease by fourfold as early as 3-6 months following successful treatment. The Non-Treponemal Antibody Assay (RPR) is the only assay necessary for evaluation upon reinfection since the Treponemal Antibody Assay (Syp Ab) will be positive for decades if not for life in an individual who has been previously infected. If the Treponemal Antibody has an index between 1.0 and 7.0 and the patient is Non-Treponemal Antibody negative, then a TrepSure Assay will be performed. The TrepSure assay acts as a referee to determine if a suspicious Treponemal Antibody (Syp Ab) result is a true positive, false positive or an inconclusive result needing recollection and retesting in 2-4 weeks. Any true positive Syphilis Antibody testing will be reported to the state health department.
Notes The Treponemal Antibody screen reactive specimens will reflex to an Non-Treponemal Antibody (RPR) and titer (Test Code 5500605), if necessary, at additional charge(s). The Non-Treponemal Antibody (RPR) assay is performed to distinguish recent/active from past infection.  Weakly positive SYP AB screen specimens will reflex a second treponemal assay Treponemal Antibodies, TPPA (Test Code 5501065), if necessary, at additional charge(s). The presence of maternal Treponemal Antibody (Syphilis specific Antibody) in a baby can be detected up to 15-18 months. Therefore, only a Non-Treponemal antibody (RPR) [5500605] assay will be performed on babies <18 months.

Click Here to view testing algorithm.
CPT Code(s) 86780 (possible 86780 and 86592)
Lab Section Chemistry