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OJHAS: Vol. 4, Issue
3: (2005 Jul-Sep) |
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Biological false reactive VDRL test among the HIV-infected patients: A note on
its prevalence |
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Viroj Wiwanitkit
Department of Laboratory Medicine, Faculty of Medicine,
Chulalongkorn University,
Bangkok, Thailand |
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Address For Correspondence |
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Viroj Wiwanitkit,
Department of Laboratory Medicine,
Faculty of Medicine,
Chulalongkorn University,
Bangkok, Thailand 10330
E-mail:
wviroj@yahoo.com |
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Wiwanitkit V.
Biological false reactive VDRL test among the HIV-infected patients: A note on
its prevalence.
Online J Health Allied Scs.2005;3:2 |
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Submitted: Aug 22,
2005; Revised: Oct 25, 2005; Accepted: Nov 1, 2005; Published:
Nov 30, 2005 |
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| Abstract: |
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Presently, the screening of syphilis is dependent mainly on serological tests.
In the sexually transmitted disease clinic, syphilis serology is a basic screening
test.
The results VDRL test among of 150 HIV (82 males, 68 females) infected,
regardless to immune status (CD4+ count), were studied. It was found that in 2
cases, the VDRL was biologically false reactive (VDRL positive, TPHA negative), who
had CD4+ count >200 /mL, giving the incidence rate equal to 1.3 % (1.2 %
for male and 1.5 % for female).
Key Words:
HIV, Syphilis, VDRL,
False positive |
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Syphilis is a disease caused by a spiral organism,
Treponema pallidum. Presently,
the screening of syphilis is dependent mainly on serological tests.
In the sexually transmitted disease
(STD) clinic, syphilis serology is a basic screening
test. In addition, this test is always requested routinely accompanied with
the Anti HIV serology test. Since routine syphilis screening is routinely carried
out by means of a non-treponemic reaction such as VDRL. A positive VDRL test,
should be confirmed by treponemic techniques such as fluorescent treponemal
antibody absorption (FTA-ABS) and/or hemagglutination (TPHA) and therefore the interpretation
of the VDRL results must be carefully done[1] as biological false
reactive VDRL can be seen. The recent report of Griemberg et al [1], mentioned
the rate of biological false positive equaled to 0.66 %. However, the rate of
biological false reactive VDRL among the HIV-infected patients is rarely mentioned.
Here, the author reports the rate of biological false reactive among Thai HIV-infected
patients.
This study was designed as a descriptive retrospective study. A review of VDRL
laboratory results of the HIV infected patients who attended the physician at
the Sexually Transmitted Disease Clinic, King Chulalongkorn Memorial Hospital during
year 2001 - 2004 was performed. In this study, VDRL test was performed in the
same laboratory or in different laboratories (with related quality control and
range of values) by standard method. The study on the VDRL results of 150 HIV
(82 males, 68 females) infected, regardless to immune status (CD4+ count), was
performed. The rate of biological false reactive VDRL results was determined
(VDRL reactive, TPHA negative). Descriptive statistical
analysis was performed where appropriate. Comparison between rates was performed
using Fishers exact test. P value less than 0.05 was accepted as statistical
significance level.
In this study, the VDRL biological false reactive was detected in 2 cases, who
had CD4+ count >200/mL, giving the incidence rate equal to 1.3% (1.2%
for male and 1.5% for female). However, the 2 cases with biological false positive,
after blood test, was lost for the following up, therefore, the seroconversion
pattern or relevant clinical findings could not be studied. Since not all HIV
infected patients had got CD4+ count test, it is impossible to further analyze
the correlation between CD4+ count status and biological false positive VDRL.
The present epidemic
of syphilis is related to the relapse into unsafe
sexual behavior.[2] The most widely used screening tests for syphilis are the VDRL and the rapid plasma reagin (RPR) and for confirmation the FTA and the
TPHA tests.[3] Flores noted that syphilis was common in HIV-infected patients,
who may have an altered antibody response to infection and an apparent increased
incidence of neurologic complications.[4] In addition, syphilis is occurring
in a substantial number of patients infected with the HIV, thus adding to the
complexities of diagnosis and treatment.[4] In a recent study, active syphilis
was reported in 151 of 11,368 HIV infected patients (1.33%).[5]
There are a few reports of VDRL status in HIV individuals. Fewer reports on
the biological false positive VDRL in HIV individuals are documented. In this
work, the author studied the rate of biological false reactive VDRL among the
HIV-infected patients. Of interest, in this study, the rate is significantly lower
(by Fishers exact test) than a recent previous report among prostitutes in India
(10/94, about 10.6 %).[6] In the general population, the biological
false positive VDRL generally returns to negative within 14 weeks, without other
clinical significance.[7] However, in this study it was not possible to follow up the cases with biological false positive VDRL
to ascertain the clinical course.
Further prospective study on the HIV infected patients with biological false
reactive VDRL results to assess the seroconversion pattern and possible silent
abnormality is recommended.
The author is thankful to Professor Emeritus Phairut Deesudchit, STD Clinic,
King Chulalongkorn Memorial Hospital, Thailand for giving the valuable suggestion
for performing this study.
- Griemberg G, Ravelli MR, Etcheves PC, Orfus G, Pizzimenti MC. Syphilis and
pregnancy. Prenatal control, seroprevalence and false biological positives.
Medicina 2000;60:343-7
- Janier M. Syphilis: clinical, biological and therapeutical aspects.
Rev Prat
2004;54:376-82
- Lowhagen GB. Syphilis: test procedures and therapeutic strategies.
Semin
Dermatol 1990;9:152-9.
- Flores JL. Syphilis. A tale of twisted
treponemes. West J Med 1995;163:552-9
- Schofer H, Imhof M, Thoma-Greber E
et al. Active syphilis in HIV infection: a multicentre retrospective
survey. The German AIDS Study Group (GASG). Genitourin Med 1996;72:176-81.
- Ganapathysundaram S, Mallika M, Chandrasekaran S, Mohan G. MHA-Tp testing
on HIV positive and negative women in vigilance home at Madurai. Indian J Pathol Microbiol
1992;35:44-7
- Wiwanitkit V. Biological false reactive VDRL tests: when to re-test?
Southeast
Asian J Trop Med Public Health 2002;33 Suppl 3:131-2.
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