Sexually Transmitted Infections (STIs)
Understand the Risks. Recognise the Signs. Know When to Test.
Sexually transmitted infections can affect anyone and may not always cause noticeable symptoms. Learning how STIs spread, recognising possible warning signs, and knowing when to consider testing can help protect your health and support early treatment when needed.
Clear health information · Confidential testing · Professional laboratory services
What Are Sexually Transmitted Infections?
Sexually transmitted infections, commonly known as STIs, are infections caused by bacteria, viruses, or parasites that can be passed from one person to another through sexual contact.
Some STIs may also spread through contact with infected blood or from mother to baby during pregnancy, childbirth, or breastfeeding. Many infections do not cause noticeable symptoms, which means a person may have an STI without knowing it.
Treatment depends on the infection. Some STIs can be cured with appropriate medication, while others can be treated and managed to reduce symptoms, complications, and the risk of transmission.
Why STI Testing Matters
Many sexually transmitted infections cause no symptoms or only mild symptoms. This means a person may have an infection and pass it to others without knowing it.
Testing can help detect an infection earlier, support timely treatment, and reduce the risk of long-term health complications. Depending on the infection, untreated STIs may affect reproductive health, pregnancy, the immune system, or other areas of the body.
STI testing may be important even when you feel well, particularly after a possible exposure, when starting a new relationship, or as part of routine sexual health care.
When Should You Consider STI Testing?
STI testing may be appropriate even when you do not have symptoms. The tests you need will depend on your personal circumstances, possible exposure, symptoms, and medical history.
Consider STI testing if:
- You have had unprotected sexual contact or a possible exposure
- You are starting a new sexual relationship
- You or your partner have multiple sexual partners
- A current or previous partner has received a positive STI result
- You notice unusual discharge, sores, irritation, itching, pelvic discomfort, or burning during urination
- You are planning a pregnancy
- You have previously been treated for an STI and require follow-up
- A healthcare professional has recommended testing
- You want routine sexual health screening for reassurance
Testing after a recent exposure: Some infections cannot be detected immediately after exposure. The appropriate testing time depends on the infection and laboratory method, and repeat testing may sometimes be recommended. Please tell Andalab when the possible exposure occurred.
Common Sexually Transmitted Infections
Sexually transmitted infections can be caused by bacteria, viruses, or parasites. They may spread through sexual contact and can affect people of any age, background, or relationship status.
Some STIs cause noticeable symptoms, while others may remain unnoticed for a long time. Learning about common infections, how they may spread, and the possible signs to look for can help you make informed decisions about testing and your sexual health.
Explore the sections below to learn more about common STIs, including chlamydia, gonorrhoea, syphilis, HIV, hepatitis B and C, genital herpes, trichomoniasis, and human papillomavirus.
Chlamydia
What Is Chlamydia?
Chlamydia is a common sexually transmitted infection caused by the bacterium Chlamydia trachomatis. It can affect both men and women and is transmitted through sexual contact with someone who has the infection.
Possible Symptoms
Chlamydia often causes no noticeable symptoms. When symptoms occur, they may include:
- Unusual vaginal or penile discharge
- Burning or discomfort during urination
- Pelvic or lower abdominal pain
- Pain or swelling in the testicles
- Bleeding between periods or after sexual intercourse
Why Testing Matters
When left untreated, chlamydia may lead to complications affecting reproductive health. Laboratory testing may use a urine sample or vaginal swab, depending on the individual and the test method.
Treatment
Chlamydia can be treated with appropriate antibiotics. Sexual partners may also require testing and treatment to reduce the risk of reinfection.
Gonorrhoea
What Is Gonorrhoea?
Gonorrhoea is a sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. It can affect both men and women and is transmitted through sexual contact with someone who has the infection.
Possible Symptoms
Gonorrhoea often causes no noticeable symptoms. When symptoms occur, they may include:
- Burning or discomfort during urination
- Unusual vaginal or penile discharge
- Bleeding between periods
- Pelvic or lower abdominal pain
- Pain or swelling in the testicles
Why Testing Matters
When left untreated, gonorrhoea may lead to complications affecting reproductive health. In women, it may cause pelvic inflammatory disease, fertility problems, or ectopic pregnancy. In men, it may cause painful inflammation around the testicles.
Treatment
Gonorrhoea can be cured with appropriate antibiotic treatment. Sexual partners may also require testing and treatment to reduce the risk of reinfection. Because antibiotic-resistant strains are increasing, treatment should follow current medical guidance.
Syphilis
What Is Syphilis?
Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It spreads mainly through direct contact with a syphilis sore during sexual activity and can also be passed from mother to baby during pregnancy.
Possible Symptoms
Syphilis develops in stages, and symptoms may change or disappear over time. Possible signs include:
- One or more firm, round, and usually painless sores
- A skin rash, including on the palms of the hands or soles of the feet
- Swollen lymph nodes
- Fever, sore throat, headache, or muscle aches
- Patchy hair loss or unusual tiredness
- No noticeable symptoms during the latent stage
Why Testing Matters
Symptoms may disappear even when the infection remains in the body. Without treatment, syphilis can progress and may eventually affect the brain, nervous system, eyes, ears, heart, blood vessels, and other organs. Testing is usually performed using a blood sample.
Treatment
Syphilis can be cured with appropriate antibiotic treatment. However, treatment may not reverse damage caused by a long-standing infection. Sexual partners may also require testing and treatment, and follow-up testing may be recommended.
HIV
What Is HIV?
HIV, or human immunodeficiency virus, attacks the immune system, particularly cells that help the body fight infections. Without treatment, HIV can progress to acquired immunodeficiency syndrome (AIDS).
Possible Symptoms
Some people experience flu-like symptoms within the first few weeks after infection, while others may have no noticeable symptoms. Possible early symptoms may include:
- Fever or chills
- Sore throat
- Swollen lymph nodes
- Skin rash
- Muscle aches or unusual tiredness
Why Testing Matters
Symptoms alone cannot confirm HIV infection, and a person may live with HIV for years without feeling unwell. An HIV test is the only way to know your HIV status. Testing soon after a possible exposure may need to be repeated because different HIV tests have different detection windows.
Treatment
HIV currently has no cure, but effective antiretroviral treatment can control the virus and help people with HIV live long, healthy lives. Starting treatment as soon as possible after diagnosis also protects the immune system and helps prevent transmission.
Looking for an HIV test? View our confidential HIV testing service in Phuket.
Hepatitis B
What Is Hepatitis B?
Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). It may cause a short-term infection or develop into a chronic, long-term condition.
How It Spreads
Hepatitis B can spread when infected blood, semen, or other body fluids enter another person’s body. It may be transmitted through sexual contact, shared needles, exposure to infected blood, or from mother to baby during childbirth.
Possible Symptoms
Many people with hepatitis B experience no noticeable symptoms. When symptoms occur, they may include:
- Unusual tiredness
- Fever or joint pain
- Loss of appetite
- Nausea, vomiting, or abdominal pain
- Dark urine or pale-coloured stools
- Yellowing of the skin or eyes
Why Testing Matters
Chronic hepatitis B may gradually damage the liver and increase the risk of cirrhosis and liver cancer. Blood testing can help identify current infection, previous exposure, or immunity.
Prevention and Treatment
Vaccination is the most effective way to prevent hepatitis B. Acute infection is usually managed with supportive care, while some people with chronic hepatitis B may require antiviral treatment and regular monitoring of their liver health.
Hepatitis C
What Is Hepatitis C?
Hepatitis C is a liver infection caused by the hepatitis C virus (HCV). It may cause a short-term infection or develop into a chronic, long-term condition.
How It Spreads
Hepatitis C is primarily transmitted through contact with infected blood. Sexual transmission is possible, particularly when sexual activity involves exposure to blood, but it is less common than blood-to-blood transmission.
Possible Symptoms
Many people with hepatitis C experience no noticeable symptoms. When symptoms occur, they may include:
- Fever or unusual tiredness
- Loss of appetite
- Nausea or vomiting
- Abdominal or joint pain
- Dark urine or pale-coloured stools
- Yellowing of the skin or eyes
Why Testing Matters
Chronic hepatitis C can gradually damage the liver and may lead to cirrhosis, liver failure, or liver cancer. Initial blood testing usually detects hepatitis C antibodies, while an additional HCV RNA test may be needed to confirm an active infection.
Prevention and Treatment
There is currently no vaccine against hepatitis C. However, modern antiviral medicines can cure most people with the infection. Early diagnosis and treatment can help prevent serious liver damage and reduce the risk of transmission.
Genital Herpes
What Is Genital Herpes?
Genital herpes is a sexually transmitted infection caused by herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2). It is a lifelong infection, although symptoms and outbreaks vary between individuals.
How It Spreads
Genital herpes can spread through vaginal, anal, or oral sexual contact. Transmission can occur through contact with a herpes sore, infected body fluids, or affected skin, even when no visible sores are present.
Possible Symptoms
Many people have no symptoms or only mild symptoms. When symptoms occur, they may include:
- One or more blisters around the genitals or mouth
- Painful sores after the blisters break
- Itching, tingling, or discomfort in the affected area
- Pain or burning during urination
- Fever, body aches, or swollen lymph nodes during the first outbreak
Why Testing Matters
Mild symptoms may be mistaken for other skin conditions, and the virus can be transmitted even when symptoms are absent. Testing may involve collecting a sample from an active sore. In some situations, a blood test may be used to look for HSV antibodies.
Treatment
There is currently no cure for genital herpes. However, antiviral medicines can shorten or reduce outbreaks and lower the likelihood of passing the infection to a sexual partner.
Trichomoniasis
What Is Trichomoniasis?
Trichomoniasis is a sexually transmitted infection caused by the protozoan parasite Trichomonas vaginalis. It can affect both women and men and is transmitted mainly through sexual contact.
Possible Symptoms
Many people with trichomoniasis have no noticeable symptoms. When symptoms occur, they may include:
- Unusual vaginal or penile discharge
- Genital itching, irritation, or discomfort
- Burning or discomfort during urination
- Pain or discomfort during sexual intercourse
- Redness or soreness around the genital area
Why Testing Matters
Because symptoms may be mild or absent, the infection can remain undetected and be passed to sexual partners. Laboratory testing may use a urine sample or vaginal swab, depending on the individual and the test method.
Treatment
Trichomoniasis can be cured with appropriate prescription treatment. Sexual partners should also receive medical advice and may require treatment to reduce the risk of reinfection. Sexual contact should be avoided until treatment has been completed as advised.
Human Papillomavirus (HPV)
What Is HPV?
Human papillomavirus, or HPV, is a very common group of viruses transmitted mainly through intimate skin-to-skin and sexual contact. Different HPV types can affect the genital area, mouth, or throat.
Possible Symptoms
Most people with HPV have no noticeable symptoms. Some types may cause genital warts, while high-risk HPV types can cause abnormal cell changes that may develop into cancer over time.
- Genital warts or small growths around the genital area
- No noticeable symptoms in many cases
Why Testing Matters
Most HPV infections clear naturally within two years. However, a persistent infection with certain high-risk HPV types may increase the risk of cervical and other cancers. HPV DNA testing can help identify high-risk types associated with cervical cell changes.
Prevention and Follow-Up
HPV vaccination provides protection against several important cancer-causing and wart-causing HPV types. Regular cervical screening and appropriate follow-up of abnormal results can help detect changes before they develop into cancer.
How to Reduce the Risk of STIs
Sexually transmitted infections cannot always be prevented completely, but several steps can help reduce the risk of infection and transmission.
- Use condoms correctly and consistently during vaginal, anal, or oral sex
- Discuss sexual health and STI testing with new partners
- Consider regular screening when you have new or multiple sexual partners
- Avoid sexual contact when sores, unusual discharge, irritation, or other symptoms are present
- Complete any prescribed treatment and follow medical advice before resuming sexual activity
- Encourage partners to seek testing or treatment when appropriate
- Consider vaccination against hepatitis B and human papillomavirus (HPV)
Condoms can substantially reduce the risk of many infections, although they may not provide complete protection against infections spread through uncovered skin or sores.
Regular testing, open communication, and timely medical care are important parts of maintaining sexual health.
Confidential STI Testing at Andalab
If you are considering STI testing, Andalab offers a range of confidential screening options designed for different testing needs.
Our available packages include focused blood tests, PCR testing, and broader screening combinations for common sexually transmitted infections. Sample requirements may include blood, urine, or a vaginal swab, depending on the selected package.
Explore the available tests, sample requirements, turnaround times, and transparent pricing to find the screening option that best suits your needs.
Why Choose Andalab Medical Laboratory?
✔ ISO 15189:2022 Accredited — Main Phuket Laboratory
✔ Confidential and professional STI testing
✔ High-quality laboratory testing with strict quality control
✔ Modern diagnostic technology
✔ Experienced and professional laboratory staff
✔ Fast turnaround time for many laboratory tests
✔ Convenient location in Phuket
✔ Clear and transparent package pricing
