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CORRESPONDENCE |
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| Year : 2012 | Volume
: 57
| Issue : 5 | Page : 414 |
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| Authors' Reply |
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Surajit Nayak, Basanti Acharjya
Department of Skin and VD, MKCG Medical College and Hospital, Berhampur, Orissa, India
| Date of Web Publication | 3-Sep-2012 |
Correspondence Address:
Surajit Nayak
Department of Skin and VD, MKCG Medical College and Hospital, Berhampur, Orissa
India
 Source of Support: None, Conflict of Interest: None  | Check |
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How to cite this article:
Nayak S, Acharjya B. Authors' Reply. Indian J Dermatol 2012;57:414 |
Sir,
Thanks for such valuable comments and pointing out of some mistakes by authors. [1]
According to US preventive services task force's recommended statement, screening for syphilis infection is a 2-step process that involves an initial nontreponemal test (venereal disease research laboratory [VDRL] or rapid plasma reagin [RPR]) followed by a confirmatory treponemal test (fluorescent treponemal antibody-absorption [FTA-ABS] or Treponema pallidum  rticle agglutination [TP-PA]) (http://www.uspreventiveservicestaskforce.org/3rduspstf/syphilis/syphilrs.htm). The decision on which test or tests a laboratory uses depends on several factors including cost, ease of use, compatibility with other tests, performance characteristics, and whether the aim is to detect all stages of syphilis or only infectious syphilis. (SYPHILIS Serge I Nesteroff BSc Institute of Clinical Pathology and Medical Research Centre for Infectious Diseases and Microbiology Laboratory Services Westmead, NSW.)
In the United States and certain European countries such as France and Belgium, nontreponemal tests are used for screening. One advantage of this approach is that it does not detect most adequately treated cases, thus simplifying patient assessment. There are, however, disadvantages to this approach. Screening undiluted specimens with a nontreponemal test alone can yield false negative results because of the prozone phenomenon. Nontreponemal tests also lack sensitivity in late stage infection and are subject to biological false positive reactions. Because of these limitations, many laboratories have been using a combination of a nontreponemal and a treponemal test for screening. The combination gives a sensitive and specific screen: the nontreponemal test traditionally more sensitive in early infection, the treponemal test able to detect late stage or treated infection, and with fewer false positive results.
But definitely dark ground microscopy (DGM) is an inexpensive, rapid, sensitive, and specific test, which allows immediate diagnosis and treatment of syphilis, preventing further transmission and enabling early partner notification. Because of interference from commensal spirochaetes that are found in the normal flora of the genital and rectal mucosae, DGM is considered to be less reliable in examining rectal and nonpenile genital lesions.
DGM is not suitable for examining oral lesions.
As commented by author, the nontreponemal tests VDRL/RPR are both flocculation tests, it was not denied in my article. The original Wassermann test was a complement fixation test presumed to detect antibodies to treponemes has a similar basis, as in VDRL and RPR where antibody is detected by subjecting the serum to an antigen, though one is a complement fixation test and other is a flocculation test. Although the name "Wassermann" is still used by some to refer to any nontreponemal or serologic test for syphilis, the Wassermann test as such is no longer performed. For the sake of correct usage the term should be dropped.
Yes, I should have mentioned result interpretation as reactive/nonreactive in all places, instead of positive or negative, which I have emphasized in my subject earlier.
As far as the last point is concerned, it does not require any explanation as it is rather an important input.
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| 1. | Nayak S, Acharjya B. VDRL test and its interpretation. Indian J Dermatol 2012;57:3-8. 
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