TB Blood Tests Explained (before BCG)
6-minute read · Reviewed by the Veritas Clinical Team · Last updated July 2026
Whether you’re starting a nursing course, applying for a role in healthcare, or planning long-term travel, you may have been asked to arrange TB screening or a BCG vaccine. The two are often confused, so this guide walks through what each one actually involves, and how to work out which applies to you.
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“I’m starting a nursing course and they’ve asked for a TB test. Do I also need the BCG vaccine?”
It’s one of the most common questions we hear at the counter. The answer depends on your age, whether you’ve had BCG before, your risk of TB exposure, and the result of any screening test. Understanding the difference between testing for TB and vaccinating against it helps make sense of what’s actually being asked of you.
A negative TB test doesn’t automatically mean you need the BCG vaccine. Eligibility depends on your age, occupation, previous vaccination history and an individual risk assessment. At Veritas Pharmacy, we look at all of these factors together before recommending vaccination, rather than treating a test result in isolation.
Based on UK Health Security Agency and Green Book guidance on BCG vaccination.What is tuberculosis (TB)?
Tuberculosis is a bacterial infection that mainly affects the lungs, spread through the air when someone with active TB coughs or sneezes. Most people who breathe in the bacteria never become unwell, their immune system contains it, and it stays inactive (latent) for life. In a smaller number of people, it develops into active TB disease, which needs treatment.
TB only exists overseas and isn’t something to think about in the UK.
TB still occurs in the UK, though rates are considerably lower than in many other countries. Screening remains part of standard practice for certain courses, jobs and travel plans.
Need TB screening for a course or new role?
Same-week appointments available. No GP referral needed.
What is the BCG vaccine?
BCG is a vaccine that helps protect against TB, particularly its more severe forms. It’s a live vaccine, meaning it contains a weakened form of a TB-related bacterium, which is why checking you don’t already have TB infection matters before it’s given.
No vaccine offers complete protection, but BCG has been shown to meaningfully reduce the risk of severe TB, particularly in young children. It’s one reason it remains part of routine practice for higher-risk groups, even though the wider population BCG programme in UK schools was phased out some years ago.
Who may benefit from BCG vaccination?
Eligibility is assessed individually, but the vaccine is generally considered for the following groups:
Babies and young children at higher risk
Including those born in, or with close family from, a country with higher TB rates.
Healthcare workers
Those with a realistic risk of occupational exposure to TB.
Long-term travellers
Typically staying more than three months in a higher-incidence country with close local contact.
Laboratory and occupational staff
Where work may involve handling TB-related samples or materials.
Do you need a TB test first?
This depends on whether you’ve had BCG before.
A repeat vaccine usually isn’t needed. Bring any documentation or point out your scar at your appointment.
Your pharmacist will carry out a risk assessment and may recommend a TB blood test or Mantoux test first, to confirm you don’t already have TB infection.
What happens at your appointment?
A conversation about why you need screening or vaccination, and any relevant deadlines.
Your pharmacist reviews your health history and any previous BCG vaccination.
Working out whether testing, vaccination, both, or neither is appropriate for you.
A blood test or Mantoux test, booked as its own appointment.
Booked as a follow-up once your result is confirmed clear.
What to expect afterwards and who to contact with any concerns.
Can I have a BCG vaccine as an adult?
Yes, some adults may be eligible following an individual risk assessment, particularly healthcare workers and certain travellers.
Can I have a TB blood test instead of the BCG vaccine?
They serve different purposes, a blood test checks for infection, the vaccine helps provide protection, so one doesn’t simply substitute for the other. Your pharmacist will advise which applies to you.
When should you seek medical advice?
Screening and vaccination are routine, planned appointments. The following is a general guide to how urgently to act if you notice symptoms.
- University or course screening requirements
- Employment or occupational health checks
- Pre-travel advice for an upcoming trip
- Close contact with someone recently diagnosed with TB
- A persistent cough lasting several weeks
- Coughing up blood
- Unexplained, significant weight loss
- Night sweats or a persistent fever
These symptoms need assessment by a GP, NHS 111, or A&E as appropriate, rather than a pharmacy appointment.
How Veritas Pharmacy can help
TB blood testing
Single-visit IGRA blood test, results in a few working days.
BCG vaccination
Booked once a clear test result is confirmed, where needed.
Travel vaccinations
Full destination-specific travel health consultations.
Private pharmacist consultation
General health queries and medicine reviews.
- TB testing and BCG vaccination serve different purposes.
- Not everyone needs the BCG vaccine, eligibility is assessed individually.
- A clear BCG scar or documented history may mean testing isn’t needed.
- Veritas Pharmacy offers TB screening and BCG vaccination for eligible patients.
Related reading
Travel vaccinations for healthcare workers
Do I need a hepatitis B vaccine?
Understanding TB blood tests
Travel health checklist
Not sure whether you need testing, vaccination, or both?
Whether it’s for university, a new role, or travel, our clinical team can talk you through what applies to your situation.
Free pharmacist consultation. GPhC registered. No pressure to book.
The information in this post is for general information purposes. It is not intended to replace medical advice from a healthcare professional. We make an effort to keep the content on this page up to date and accurate.
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