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Case report and evaluation of the frequency of the prozone phenomenon in syphilis serology – an infrequent but important laboratory phenomenon
Jeffrey J.
Post
A
B
C
E
,
Candice
Khor
A
B
C
,
Virginia
Furner
B
,
Don E.
Smith
B
,
L. Ross
Whybin
D
and
Peter W.
Robertson
D
A
Department of Infectious Diseases, Prince of Wales Hospital, Randwick, NSW 2031, Australia.
B
Albion Street Centre, Prince of Wales Hospital, Surry Hills, NSW 2010, Australia.
C
Prince of Wales Clinical School, University of New South Wales, Randwick, NSW, Australia.
D
Department of Microbiology, Serology Laboratory, South Eastern Area Laboratory Services, Prince of Wales Hospital, Randwick, NSW, Australia.
E
Corresponding author. Email: Jeffrey.Post@sesiahs.health.nsw.gov.au
Sexual Health
9(5)
488-490 http://dx.doi.org/10.1071/SH11156
Submitted: 9 November 2011 Accepted: 1 May 2012 Published:
10
September
2012
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Abstract
Background:
Treponema pallidum specific serology generally remains reactive for life. Therefore, the diagnosis of syphilis reinfection relies on clinical assessment and nontreponemal (reagin) serologic testing. The prozone phenomenon can lead to a falsely nonreactive rapid plasma reagin (RPR) assay result.
Methods: We report a case of secondary syphilis in a HIV infected patient with a previous history of syphilis infection, where a falsely nonreactive RPR assay was associated with a delayed diagnosis of reinfection and infectious syphilis. The prozone phenomenon was detected in several of the patient’s serum samples collected around this time. We subsequently undertook a prospective evaluation for the prozone phenomenon in 3222 consecutive sera, which were assayed using the RPR assay for clinical purposes over a 10-month period.
Results: The overall rate of the prozone phenomenon was 2 out of 3222 samples (0.06%; 95% confidence interval (CI): 0.02–0.22%) and the rate per reactive sample was 2 out of 397 (0.5%; 95% CI: 0.14–1.81%).
Conclusion: Clinicians should request RPR testing at dilutions of sera when syphilis is suspected clinically and the RPR assay is nonreactive.
Additional keywords:
false negative reactions, HIV, serology, testing.
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References
[1]
Jin F, Prestage GP, Kippax SC, Pell CM, Donovan BJ, Kaldor JM,
et al
Epidemic syphilis among homosexually active men in Sydney.
Med J Aust 2005
; 183: 179–83.
|
PubMed |
[2]
Botham SJ, Ressler K-A, Bourne C, Ferson MJ.
Epidemic infectious syphilis in inner Sydney – strengthening enhanced surveillance.
Aust N Z J Public Health 2006
; 30: 529–33.
|
CrossRef |
PubMed |
[3]
The Kirby Institute. HIV, viral hepatitis and sexually transmissible infections in Australia annual surveillance report 2011. Sydney: The Kirby Institute, University of New South Wales; 2011.
[4]
Larsen SA, Steiner BM, Rudolph AH.
Laboratory diagnosis and interpretation of tests for syphilis.
Clin Microbiol Rev 1995
; 8: 1–21.
|
CAS |
PubMed |
[5]
Jurado RL, Campbell J, Martin PD.
Prozone phenomenon in secondary syphilis. Has its time arrived?
Arch Intern Med 1993
; 153: 2496–8.
|
CrossRef |
CAS |
PubMed |
[6]
Spangler AS, Jackson JH, Fiumara NJ, Warthin TA.
Syphilis with a negative blood test reaction.
JAMA 1964
; 189: 87–90.
|
CrossRef |
CAS |
PubMed |
[7]
el-Zaatari MM, Martens MG, Anderson GD.
Incidence of the prozone phenomenon in syphilis serology.
Obstet Gynecol 1994
; 84: 609–12.
|
CAS |
PubMed |
[8]
Smith G, Holman RP.
The prozone phenomenon with syphilis and HIV-1 co-infection.
South Med J 2004
; 97: 379–82.
|
CrossRef |
PubMed |
[9]
Nnoruka EN, Ezeoke ACJ.
Evaluation of syphilis in patients with HIV infection in Nigeria.
Trop Med Int Health 2005
; 10: 58–64.
|
CrossRef |
CAS |
PubMed |
[10]
Hunter MG, Robertson PW, Post JJ.
Significance of isolated reactive treponemal chemiluminescence immunoassay results.
J Infect Dis
; : .
|
CrossRef |
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