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Test Code RPRB or LAB3359 Rapid Plasma Reagin (RPR), Infant, Serum

Important Note

As an initial screening order, RPRB (LAB3359) is only available for patients < 6 months of age. Because reagin antibody may develop later in newborns, a nonreactive RPR does not exclude congenital syphilis. All RPR’s (reactive and nonreactive) done on neonates up to the age of 6 months are sent to the MDCH for confirmatory testing.

Patients > 6 months of age will have RPRB orders converted to SYPHG (LAB2594). 

RPRB (LAB3359) is also a part of the Syphilis Reverse Algorithm and is reflexed if the SYPHG result is positive or equivocal. 

If monitoring patients for syphilis treatment, please order RPRTX (LABXXX).

Specimen Requirements

Container Type:

Optimal: Gold

Acceptable: Red
Optimal Collection Volume: 

5 mL
Minimum Volume:

2 mL
Collection Instructions:

Gently invert the sample 5-6 times after collection.
Specimen Transport:

Refrigerate
Processing Instructions: 

1. Allow the sample to clot for 30 minutes.

2. Centrifuge specimen within 2 hours of collection.

3. Separate serum into a false bottom container.

4. Keep serum refrigerated until testing can be performed.

Specimen Stability

Specimen Type Temperature Time
Serum

Refrigerated

 5 days

Specimen Rejection Criteria

Quantity not sufficient

Useful For

All neonates born to mothers who have reactive nontreponemal and treponemal test results should be evaluated with a quantitative nontreponemal serologic test (RPR or VDRL) performed on the neonate's serum because umbilical cord blood can become contaminated with maternal blood and yield a false-positive result, and Wharton's jelly within the umbilical cord can yield a false-negative result. The nontreponemal test performed on the neonate should be the same type of nontreponemal test performed on the mother.

Methodology

Coagglutination

Reference Ranges

Nonreactive

Day(s) Performed

Monday, Wednesday, and Friday - Day shift

Expected TAT

Same day or1-2 days

Performing Laboratory

Bronson Laboratory, Chemistry - Kalamazoo

Sample Retention Time

7 days

CPT Code

  • RPR - 86592
  • RPR Titer (performed if RPR is reactive) - 86593

LOINC Code

20507-0

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