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Sexually Transmitted Diseases (STDs), also called Sexually Transmitted Infections (STIs) are infections that are transmitted by direct contagion through sexual contact, and in which the pathogen responsible for the clinical picture can be a bacterium, a virus, a fungus or even a protozoan. There are several tests that can be used to diagnose a sexually transmitted infection, and, in this article, we will analyze the main features of each method and the tests available in our analysis laboratory.


They are usually caused by bacteria, viruses, and protozoa that pass from one individual to another through the direct contact, mucous membranes, of infected biological fluids. These pathologies can affect the genitals or other organs and can lead to numerous complications such as immunodeficiency, tumours, cardiovascular complications, and infertility. Sexually transmitted infections can go undetected for a long time and signs and symptoms can appear, depending on the type of infection, from a few days to a few years after exposure.

These infections can sometimes be asymptomatic, which makes them difficult to detect but more importantly the biggest reason behind underdiagnosis is the stigma associated with these diseases. People who suspect that they have been infected, as in the case of unprotected risky sex, very often avoid screening tests because of the fear of being judged and the embarrassment that characterizes these kinds of situations.


It is necessary to undergo a diagnostic check-up regarding sexually transmitted diseases in the following two cases:

• When you want to confirm or exclude a diagnostic suspicion of a sexually transmitted infection.
• when you want a child, search for specific microorganisms that can impair the functioning of organs and cause male and female infertility.


The diagnosis of these diseases includes a set of serological, microbiological, and molecular tests by PCR to search for the main bacteria, viruses, and protozoa responsible for male and female sexually transmitted infections.


The serological investigation involves the research directly in the blood of the antibodies that the immune system has produced against the pathogen responsible for the infection. This is done through the quantitative and qualitative dosage of IgM antibodies, which attest to the ongoing infection, and IgG antibodies, which instead attest to a past exposure and the presence of immune memory to a specific pathogen that has previously infected the subject.

This package of tests includes blood sample investigations designed to detect hepatitis B through the research of HBsAg (Hepatitis B surface Antigen), HCV virus infection, HIV infection, and Treponema, the pathogen responsible for syphilis. The diagnosis of syphilis is made by detection of Rapid Plasma Reagin (RPR) and circulating anti-Treponema antibodies (Ac Treponema) in blood, which is currently the diagnostic gold standard.


PCR investigations are molecular investigations aimed at finding the specific genetic material of the pathogen underlying the disease. In our laboratory are available molecular tests to be performed on urine sample for:

• Chlamydia
• Gonococcus
• Trichomonas vaginalis
• Mycoplasma hominis
• Mycoplasma genitalium
• Ureaplasma urealyticum
• Ureaplasma parvum

Urine samples and PCR analysis are preferable to vaginal swabs. First Void Urine (FVU) is a good sample for detecting STI in both males and females and FVU-PCR (so PCR on FVU) is more efficient in detecting infection than endocervical and urethral swabs or semen analysis.


A combination of urine PCR and blood testing is a combined test that is extremely useful in many situations, especially for more diagnostic confirmation.

The following serologic tests in our laboratory:

• HIV test
• HCV test
• HBsAg test
• RPR test

can be paired with the following tests in PCR on urine sample:

• Chlamydia
• Gonococcus
• Trichomonas vaginalis
• Mycoplasma hominis
• Mycoplasma genitalium
• Ureaplasma urealyticum
• Ureaplasma parvum


Molecular testing by PCR for HSV is necessary in all cases in which the presence of genital herpes is clinically suspected, manifested by multiple painful ulcers in the genital region; this virus can give complications such as urethritis, meningitis and can be the basis of maternal-fetal transmission during pregnancy.

This method detects the genetic material (DNA) of HSV-1 and 2 through PCR in urine samples, so as to make a diagnosis of certainty and proceed with the therapeutic course.


Most genital HPV infections regress spontaneously. A small proportion, however, if left untreated, can slowly evolve into a cancerous form. Cervical cancer is, in fact, almost always related to the presence of HPV.

The diagnostic approach to monitoring and control HPV infection, as well as the lesions caused by it, is essentially based on clinical investigation, Pap-test, colposcopy, and molecular examination (HPV-DNA). Molecular testing, also known as HPV-DNA testing, determines the presence or absence of the viral genome, even before cervical cells develop tumour abnormalities.


A rapid diagnosis is important, both to set the right therapy and thus relieve the symptoms, and to prevent possible complications and avoid transmission to other people. STDs are treatable in most cases, through antibiotics or other specific medications prescribed by your doctor. It is important that the therapy is correct and started as soon as possible and for this reason, timely treatment is very important because it reduces the infectivity of the patient and interrupts the chain of contagions.

Getting tested is equivalent to respecting yourself and others.

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