*False-Positive Serologic Reactions for Syphilis DOI: http://dx.doi.org/10.5772/intechopen.106370*

As for chronic false-positive reactions, they can be noted in such clinical cases as hepatitis C virus (HCV) infection, intravenous drug use, malignancy, older age, malaria, Chagas disease, tuberculosis, leprosy, and connective tissue diseases [28]. Besides, false-positive test is a characteristic clinical sign in patients with systemic lupus erythematosus [42, 43]. It is proved now that false-positive results of serologic reactions for syphilis may be caused by HCV [44]. Some investigations showed that different types of cryoglobulinemia might be accompanied by acute or chronic falsepositive reactions [45].

Further investigation demonstrated that racial and environmental factors, as well as immuno-chromatographic dual syphilis rapid testing may affect [46], and that can be used in clinical practice.

Augenbraun et al. concluded that HCV infection was associated with certain mechanisms changing the immune function including alterations in serological reactions results. He underlined as well that women with HCV were more likely to have biological false-positive syphilis tests than women without HCV [47].

Furthermore, Bright et al. noted that false-positive reactions might be marked in patients treated with pooled human immunoglobulin G infusions [48].

In 2014, Liu et al. named diseases that had not been previously reported to be associated with the classical biological false-positive reaction, such as false-labor, megaloblastic anemias, aplastic anemias, redundant prepuce, congenital malformation of heart, and salpingitis [49].

Nowadays the significance of sera with isolated reactive treponemal chemiluminescence immunoassay (IRTCIA) results is being discussed. It is known that as a rule, women have this phenotype more commonly than men. Bopage et al. presented the results of the examination 19/63 (30.1%) subjects with the IRTCIA phenotype, which were positive in the line immunoblot assay (LIA). It was marked that women were substantially less likely to have definitive results (positive or negative) than men (p = 0.015). And women who were pregnant less likely than nonpregnant women to have a negative LIA result (OR 0.57; p = 0.03). Record review of 22 different women with IRTCIA reactivity allowed to reveal that 2/22 (9.1%) had HIV and previous syphilis infection, 15/22 (68.2%) were pregnant, and 3 (13.6%) had autoimmune disease [50].

McGready et al. emphasized that the potential impact of false-positive tests should be considered in HIV- positives [51]. And vice versa, false-negative lues tests are noted in HIV- positives subjects [52].

Cantor et al. analyzed a 2004 systematic review of studies of syphilis screening effectiveness, test accuracy, and screening harms in nonpregnant women and adolescents. It was proved that screening HIV-positive men or men who have sex with men (MSM) for syphilis every 3 months is associated with improved syphilis detection [53].

Today there are no doubts that HIV-positive patients [54, 55], MSM, and transgender women are at high risk of acquiring syphilis and HIV infection [56].

The results presented by Kalou et al. indicate that this assay could have a significant impact on the simultaneous screening of HIV and syphilis using a single test device for high-risk populations or pregnant women needing timely care and treatment [57]. Shakya et al. also underlined the importance of simultaneous diagnosis of HIV and syphilis [58].

Grégoire et al. presented the results of the examination of donors who had falsepositive tests for HIV, HBV, HCV, or syphilis. Rates of second false-positive results were compared by year of deferral, transmissible disease marker, gender, age, donor status (new or repeat), and testing platform (same or different) both at qualification for re-entry and afterward. The risk, when analyzed by multivariate analyses, of a second deferral for a false-positive result, both at qualification and 3 years after reentry, was lower for donors deferred on a different platform; this risk was higher for HIV, HCV and syphilis than for HBV and for new donors if tested on the same platform [59]. The importance of thorough examination of HIV subjects with falsepositive reactions for syphilis was marked in other investigations as well [60, 61].

Sandes et al. presented the results of analyses of the positive and false-positive tests of treponemal and nontreponemal tests in blood donors and found out that older donors and donors with lower education levels were associated with a higher risk of positivity for syphilis [62].
