Every UK newborn has the bloodspot test at 5 days old. Almost no parent knows what it tests for. Here's all 9 conditions in plain English — and critically, what a repeat test actually means.
Every newborn in the UK is offered the bloodspot screening test at around 5 days old. Almost every parent says yes without knowing what it tests for. Here's what it's looking for, what the results mean, and what to do if you're called for a repeat.
The test checks for 9 rare but serious conditions. Most are genetic — meaning they were present from conception, unrelated to anything in pregnancy, and undetectable before birth.
At around 5 days old, a midwife or health visitor pricks your baby's heel with a small lancet and collects 4 drops of blood on a special card. This is briefly uncomfortable — feeding and skin contact during or immediately after helps settle your baby.
The card is sent to the lab. Results arrive within 6 weeks of the test (usually sooner) — mostly by letter, sometimes by phone or at your health visitor appointment. The vast majority of results are 'not suspected' — meaning none of the conditions are indicated.
If a result requires follow-up, you will be contacted more quickly — typically within 2–4 weeks for conditions like sickle cell disease, and by 3 weeks for CHT and metabolic conditions, since these require early treatment.
This is the most practically important piece of information in this guide. If your midwife or health visitor calls to arrange a repeat bloodspot test, the most common reason is a problem with the sample — an insufficient amount of blood, spots that have run together, or a card that dried incorrectly. This is routine and happens in a small percentage of samples.
A recall for a repeat test is not the same as a positive result. It means the first sample couldn't be analysed reliably. The vast majority of repeat tests come back 'not suspected'.
If there is a genuine concern about one of the conditions being present, you will be told explicitly — you will not be left to guess from a 'please come back for a repeat'. The communication at that stage is direct and includes a referral to a specialist.
A positive screening result is not a diagnosis — it is a flag that further testing is needed. Screening tests are designed to be sensitive (catch most true positives), which means some positive screens turn out to be false positives on confirmatory testing.
If your baby screens positive for one of the conditions:
• You will be contacted promptly and referred to a specialist paediatric team
• Confirmatory diagnostic tests will be arranged
• You will receive full information at every stage
• Treatment for most screened conditions is highly effective when started early
The purpose of newborn screening is precisely this: catching conditions before symptoms appear, so that treatment can start at a stage when outcomes are best. The detection of conditions like PKU, CHT, or MCADD in the first weeks of life, before any symptoms develop, changes outcomes dramatically.
The screening is offered (recommended but not mandatory). You can decline testing for individual conditions — though sickle cell disease, cystic fibrosis, and CHT can be opted out of separately, while the six inherited metabolic diseases are tested as a group. If you have questions or concerns, discuss them with your midwife.
In some areas of England, a SCID screening pilot is ongoing. Severe combined immunodeficiency (SCID) causes serious immune system problems — babies cannot fight infections. SCID screening in some NHS regions is being evaluated for inclusion in the national programme.
The blood spot card is stored securely by the NHS for several years after testing. The stored card may be used (anonymously) for quality assurance, or you may be invited to allow it to be used in research. You can ask about your trust's storage policy if this is a concern.