What it measures
- ABO blood group
- Rhesus (RhD) factor
Who it’s for
- Pregnancy or planning a pregnancy
- Curiosity, travel or your personal medical records
- Before donating blood
The eight main blood groups
Your ABO group depends on which markers (antigens) sit on your red blood cells: A, B, both (AB) or neither (O). Your Rhesus status depends on whether you have the RhD antigen. Together that gives eight main groups, from O positive, the most common in the UK, to AB negative, the rarest.
Why RhD matters in pregnancy
If you’re RhD negative and your baby is RhD positive, your body can make antibodies against your baby’s blood cells, which can affect a later pregnancy. Anti-D injections, arranged by your NHS maternity team, prevent this. Knowing your blood group early helps you understand your care.
How to prepare
- Drink a couple of glasses of water beforehand: it makes the sample quicker and easier to take.
- No fasting needed. Eat and drink as normal.
How it works at our Croydon clinic
Book online
Choose your test and a time that suits you. No GP referral needed.
A 15-minute visit
A trained clinician takes a small blood sample at 169 Shirley Road, Croydon. Tell us if you’re nervous.
Results in 1–3 days
A clear report showing each result against its reference range.
Next steps
Share your report with your GP, who can arrange NHS follow-up if anything needs it.
Questions
Can my blood group change?
No. It’s inherited and stays the same for life, except in very rare cases such as after a bone marrow transplant.
Will a hospital use my result?
Hospitals always carry out their own checks before a transfusion or surgery. Your report is for your own information and records.
How much is a Blood Group Test in Croydon?
£70 at our clinic at 169 Shirley Road, Croydon, including taking your blood sample and your report.
How quickly will I get my results?
Usually within 1 to 3 days, in a clear report showing each result against its reference range.
Pregnant? See our pregnancy blood tests, including NIPT from £295 and the early gender blood test from 6 weeks.