Infection Blood Tests and Health Checks
Infections aren’t always easy to identify from symptoms alone and a targeted infection blood test can help investigate whether you’ve been exposed to a particular virus, bacterium, or parasite.
This test provides comprehensive screening for HIV, hepatitis B, and hepatitis C Finger-prick or Venous collection Worried about toxoplasmosis exposure? This test detects antibodies to determine whether you have a past or recent toxoplasma infection Venous collection Recently travelled to a Zika-affected area or planning pregnancy? This test detects Zika virus IgM and IgG antibodies, helping assess recent or past exposure Venous collection Are you looking for a discreet blood test to see if you carry herpes? With this test, you can find out if you carry HSV-1 (herpes simplex virus) or HSV-2 — the viruses that cause cold sores and genital herpes Venous collection Want to know if you’ve recently been exposed to or had a past infection with cytomegalovirus (CMV)? This test measures CMV antibodies, helping you understand your immune status Venous collection Check for antibodies to the virus that causes glandular fever Venous collection If you’ve had potential exposure to HIV or just want to check your status, this test provides a fast and reliable way to find out Finger-prick or Venous collection Concerned about syphilis but have no symptoms? Our test detects the presence of IgM and IgG antibodies in your blood, helping to identify whether you have a current infection or have been previously infected Finger-prick or Venous collection
“If you suspect you've had a specific infection or want peace of mind with a full screening, these tests may provide actionable insights from the comfort of your home”
Dr Susanna Hayter, Digital Clinician, Medichecks
The right test depends on the infection you’re concerned about, how you may have been exposed, and how long ago the exposure happened.
- I’m concerned about blood-borne viruses: The HIV - Hepatitis B - Hepatitis C Blood Test screens for all three infections in one profile. You can also choose the HIV Blood Test if HIV is your main concern.
- I think I may have glandular fever: The Epstein-Barr Virus Antibodies Blood Test measures a combination of EBV antibodies that can help distinguish recent from previous exposure. The Epstein-Barr Virus (EBV DNA) Blood Test checks directly for EBV genetic material and is a more specialist option.
- I’m pregnant, planning a pregnancy, or concerned after travel: The Torch Screen Blood Test screens for several infections that may affect pregnancy, while the Zika Virus Antibodies Blood Test (Flavivirus) may be appropriate following travel to an area where Zika is a concern. Speak to a healthcare professional promptly about suspected exposure during pregnancy rather than relying on private testing alone.
Testing for an infection too soon after exposure can produce a negative result before the relevant marker becomes detectable. Always check the recommended window period and preparation instructions for your chosen test.
Not every infection test looks for the same thing. Understanding the method used can help you choose the right test and interpret the result more accurately.
- Antibody tests: Look for proteins produced by your immune system following an infection. IgM antibodies are often associated with a more recent response, while IgG antibodies may remain after an infection has passed.
- Antigen tests: Look for a component of the infection itself. For example, the Hepatitis B Surface Antigen Blood Test checks for hepatitis B surface antigen, which may indicate a current infection.
- PCR and DNA tests: Look for genetic material from a virus or other organism. The Epstein-Barr Virus (EBV DNA) Blood Test checks for EBV DNA, while the Hepatitis C Quantification Blood Test measures the amount of hepatitis C virus in the blood.
FAQs
Can a blood test detect an infection?
Some infections can be detected using a blood test. Depending on the test, it may identify antibodies, antigens, or genetic material associated with a specific infection. However, no single blood test checks for every possible infection.
What infections can be detected through blood tests?
Blood tests can help investigate infections including HIV, hepatitis A, B, and C, syphilis, Epstein-Barr virus, cytomegalovirus, toxoplasmosis, Zika virus, and varicella-zoster virus. Some infections, including chlamydia and gonorrhoea, are usually detected using urine or swab samples instead.
Can you have an infection without symptoms?
Many infections can be asymptomatic, particularly in their early stages. STIs including chlamydia, gonorrhoea, and HIV may not cause obvious symptoms, which is why testing after a possible exposure is important.
How soon after exposure should I have an infection test?
The timing depends on the infection and the test method. There’s often a window period between exposure and the point when antibodies, antigens, or genetic material can be detected reliably. Testing too early may produce a negative result even if an infection is present.
How soon after unprotected sex should I take an STI test?
Different STIs have different window periods. Some infections can take several weeks to become detectable. Sexual health services commonly advise around two weeks for chlamydia and gonorrhoea, approximately six to seven weeks for HIV, and up to 12 weeks for syphilis.
Is an antibody result proof of a current infection?
Antibodies may indicate recent infection, past infection, vaccination, or immunity, depending on the antibody being measured. Further antigen, PCR, repeat, or confirmatory testing may be required.
Can an infection blood test diagnose an STI?
Some STIs, including HIV and syphilis, can be investigated using blood samples. Others, including chlamydia and gonorrhoea, are usually tested using urine or swabs. The 6-in-1 STI Blood and Urine Test combines sample types to screen for a broader group of infections.
Can I test for an infection at home?
Many private infection tests allow you to collect a finger-prick blood or urine sample at home, while others require a venous blood sample taken by a healthcare professional. A laboratory then analyses your sample.
What should I do if my infection test is positive?
Don’t assume that a positive screening result provides a final diagnosis. Contact your GP, sexual health clinic, maternity team, or another appropriate healthcare professional for advice, confirmatory testing, treatment, and guidance on protecting others where necessary.
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