Folate, also called vitamin B9, is needed to make red blood cells and to support a healthy pregnancy. Low folate causes a form of anaemia with tiredness and breathlessness, and is linked to poor diet, alcohol, some medicines and conditions that affect absorption. The test costs £68.13 plus the £50 phlebotomy fee, and results are usually available in 1 day.
No fasting is needed. Serum folate reflects recent intake, so a clinician will consider your diet and any supplements when reading the result.
Written by Mr Stephen Lingam. Reviewed by Dr Mohammad Bakhtiar (GMC 4694470) on 06/09/2026.
It shows whether your recent folate intake is enough to support red cell production. Low levels can cause anaemia.
No. There is no fasting or special preparation for a serum folate test.
B12 and folate deficiency look the same on a full blood count, and treating folate deficiency without checking B12 can mask a B12 problem.
Results are usually available in 1 day by email.