Can Routine Blood Tests Really Detect STDs? What You Need to Know

24 Sep 2025

When it comes to sexual health, testing plays a crucial role in protecting yourself and your partners. Many people assume that if they have recently had a blood test as part of a routine health check, this would automatically include screening for sexually transmitted diseases (STDs). But is this actually true? Can routine blood tests really detect STDs, or is specialist testing required?

In this article, we will break down what routine blood tests usually cover, how STD testing works, which infections can be detected by blood tests, and why seeking dedicated sexual health screening is important for peace of mind.

What are Routine Blood Tests?

Routine blood tests are a common part of general health check-ups in the UK. They are designed to provide an overall picture of your well-being by measuring key markers in your blood. Depending on your doctor or clinic, these tests may include:

• Full Blood Count (FBC) – Checks the levels of red and white blood cells, haemoglobin, and platelets.
• Liver Function Tests (LFTs) – Assesses how well your liver is working.
• Kidney Function Tests – Measures urea, electrolytes, and creatinine.
• Cholesterol Profile – Evaluates your cardiovascular health risk.
• Blood Glucose Levels – Checks for diabetes or pre-diabetes.

These are extremely useful for detecting conditions like anaemia, diabetes, liver or kidney problems, and heart disease risk. However, routine blood tests are not automatically designed to detect sexually transmitted infections.

Can Routine Blood Tests Detect STDs?

The short answer is: not usually. Routine blood tests carried out during a general health check do not automatically screen for STDs.

Most sexually transmitted infections require specific tests, and unless you specifically request STD screening, these won’t be included. For example:

• Chlamydia and Gonorrhoea are detected using swabs or urine samples, not standard blood tests.
• HIV, Syphilis, and Hepatitis B and C can be detected via blood tests, but these need to be ordered specifically as part of an STD panel.
• Herpes (HSV) can sometimes be identified through blood testing, but diagnosis is usually based on symptoms and swab samples from blisters or sores.

So, if you have had a routine blood test and want to know whether you are clear of STDs, the answer is likely to be no—unless you requested dedicated sexual health screening at the same time.

Which STDs Can be Detected with a Blood Test?

While routine blood tests don’t automatically include STD screening, some infections can indeed be identified using blood samples:

1. HIV – Detected by looking for antibodies or antigens. Early detection is vital for starting treatment and living a healthy life.
2. Syphilis – Blood tests can confirm both current and past infection.
3. Hepatitis B and C – Both can be detected in the blood and require prompt management to prevent long-term liver complications.
4. Herpes Simplex Virus (HSV) – Blood tests can sometimes detect antibodies, although this isn’t always conclusive.

These tests are highly specific and are only carried out if they are requested or if you attend a sexual health clinic.

Why Routine Blood Tests and STD Tests are Different

The main reason routine blood tests don’t usually detect STDs is that they are designed for different purposes. A standard health check looks at your general well-being, while STD screening focuses on identifying infections transmitted through sexual activity.

Testing for STDs requires different methods, such as:

• Swab Tests – from the cervix, urethra, throat, or rectum.
• Urine Samples – commonly used for chlamydia and gonorrhoea.
• Blood Tests – specifically ordered to detect HIV, syphilis, and hepatitis.

Unless these are requested, you won’t know your STD status from a general check-up.

Why Dedicated STD Testing is Important

Getting tested for STDs is essential if you are sexually active, especially if you have had unprotected sex, a new partner, or multiple partners. Many STDs do not show symptoms straight away, meaning infections can go unnoticed for months or even years.

For example:

• Chlamydia can remain symptomless but may cause infertility if untreated.
• Gonorrhoea can cause pelvic inflammatory disease and long-term complications.
• HIV may not show symptoms for years, but early treatment drastically improves long-term health.

This highlights why relying on a routine blood test for reassurance is not enough.

When Should You Get an STD Test?

Experts recommend testing if:

• You have had unprotected sex.
• You are starting a new relationship.
• You or your partner have multiple sexual partners.
• You are experiencing unusual symptoms (discharge, pain, sores, itching).
• It has been more than a year since your last sexual health check.

Even if you have no symptoms, regular testing is a responsible way to protect yourself and your partners.

Role of Private STI Testing

For many people, accessing NHS sexual health services can mean waiting in long queues, limited appointment availability, or concerns about privacy. In these situations, Private STI Testing in London is an excellent option.

Private testing ensures confidentiality, flexible appointment times, and rapid results. Many private clinics in London offer same-day or next-day testing, covering a wide range of infections beyond the basics. This makes it easier to stay on top of your sexual health without delays or stress.

Additionally, private testing provides a more personalised experience. You can speak openly with a doctor, receive tailored advice, and start treatment quickly if needed. Choosing Private STI Testing in London means you don’t need to worry about long waiting times or limited access to care.

What Happens During an STD Test?

If you decide to book an STD test, the process is straightforward and discreet:

1. Consultation – You’ll speak with a doctor about your concerns, sexual history, and any symptoms.
2. Sample Collection – This may involve blood tests, urine samples, or swabs depending on what infections are being tested.
3. Results – Many clinics provide results within 24–48 hours.
4. Treatment and Support – If you test positive, treatment can usually start immediately, with follow-up care if needed.

Why Early Detection Matters

Catching an STD early can make all the difference. Most infections are treatable with antibiotics or antiviral medications, and even those that are not curable, such as HIV, can be managed effectively with early treatment.

Early testing prevents complications such as infertility, pregnancy risks, or long-term organ damage. It also helps stop the spread of infections to others.

Final Thoughts

So, can routine blood tests really detect STDs? The truth is that while some STDs can be identified with blood samples, routine blood tests don’t usually include them. If you want to know your sexual health status, you need to request dedicated STD testing.

Being proactive about your sexual health is nothing to be embarrassed about. In fact, it’s one of the most responsible steps you can take for yourself and your partner. With accessible options for both NHS and private testing, there is no reason to delay.