11 of the most common STIs/STDs

• HIV 1+2 Ag/Ac Combo [4. Generación]: This test looks for HIV in two ways at once: the p24 protein, a part of the virus itself that appears very soon after infection, and antibodies, the defences your body makes against HIV-1 and HIV-2. It's also known as the fourth-generation HIV test, and infection is detectable after 10-18 days. The laboratory recommends confirming negative results at 30 days after a risk exposure.
• Hepatitis B surface antigen (HBsAg): A protein from the outer surface of the hepatitis B virus. If it's found in your blood, it shows the virus is present right now.
• Hepatitis C antibodies (anti-HCV): Antibodies your body makes against the hepatitis C virus. They show whether you've ever been in contact with the virus, and a positive result is confirmed with a second test that looks for the virus itself.
• Syphilis RPR (VDRL): A screening test for syphilis that measures antibodies your body makes in response to the infection. A positive result is confirmed with a second, more specific test, and the level is also used to follow treatment.
• Syphilis antibodies (Treponema IgG+IgM): Looks for the antibodies your body makes against Treponema pallidum, the bacteria behind syphilis. They appear from about three weeks after exposure and usually stay positive after treatment, so the lab reads them together with the RPR.
• Chlamydia (Chlamydia trachomatis): A bacterial infection passed on through vaginal, anal or oral sex. It often causes no symptoms, especially in women, and a short course of antibiotics treats it.
• Gonorrhoea (Neisseria gonorrhoeae): A bacterial infection passed on through vaginal, anal or oral sex. Men often notice burning or discharge, while in women it frequently goes unnoticed, and antibiotics treat it.
• Trichomonas (Trichomonas vaginalis): A tiny parasite passed on through sex. Most people have no symptoms, women are more likely to notice discharge or itching, and a short course of medication treats it.
• Mycoplasma hominis: A bacterium that lives in the genital area of many healthy people without causing problems. A positive result is read together with your symptoms, and often needs no treatment.
• Mycoplasma genitalium: A bacterium passed on through sex that often causes no symptoms. It needs specific antibiotics, so knowing it's there helps your doctor choose the right treatment.
• Ureaplasma parvum: One of the most common bacteria in the genital area, and usually harmless. A positive result without symptoms rarely needs treatment.
• Ureaplasma urealyticum: A bacterium commonly found in the genital area of healthy people. It sometimes causes irritation when you pee, so a positive result is read together with your symptoms.

Guidance only. A test is not a diagnosis. Detection times are approximate and vary from person to person: if the result is negative and the exposure is recent, it may need repeating. Check your results with a healthcare professional.