Tired All The Time

The things that most often sit behind persistent tiredness, on one sample. Two ways to take it: a finger prick at your kitchen table, or a fuller venous draw.

Finger prick — 11 markers, £79

• Thyroid Function — TSH, Free T3, Free T4
• Iron Profile — Iron, Total iron binding capacity, Unsaturated iron binding capacity, Transferrin saturation, Ferritin
• Vitamin D — 25-OH vitamin D
• Active Vitamin B12 — the fraction your cells can actually use
• Inflammation — hs-CRP

Iron is the marker most likely to be lost on a finger-prick sample, and you should know that before you buy. Squeezing the finger to get enough blood ruptures red cells. That is called haemolysis, and it is the most common problem with a finger-prick sample. It destroys 4 of the 5 iron markers. Only ferritin usually survives as it is measured a different way.

A haemolysed sample does not fail this test but it can cost you 4 of the 11 markers, and it keeps the one that carries the answer, because ferritin is what tells you whether your iron stores are low and the hs-CRP tells you whether that ferritin can be read at face value. Warm your hands properly and let the blood drip rather than squeezing, and you make it far less likely. The venous version does not have this problem.

Venous — 33 markers, £109

Everything above, plus:

• Full Blood Count — 20 markers, including the red cell measurements that show anaemia and what type it is
• HbA1c — three-month average blood sugar
• Folate — the third cause of anaemia alongside iron and B12

The full blood count, HbA1c and folate are all venous only. The full blood count and HbA1c fail too often on a finger prick to be worth selling that way, and folate is accredited for venous blood only. That is the whole difference between the two routes, and it is a real one: the venous version is the complete anaemia and diabetes picture, the finger-prick version is not.

Before your sample

• Warm your hands under running water for a couple of minutes first. Cold hands are the most common reason there is not enough blood.
• Let the blood drip. Squeezing or milking the finger is what ruptures the red cells and costs you the iron markers.
• Wash your hands thoroughly. No hand cream and no makeup on your fingers — iron oxide pigments can interfere with the iron result.
  
• Stay well hydrated.

Timing

Take in the morning, ideally fasted. Iron moves with both food and the hour, and thyroid reads a little differently after a meal.

The morning window matters and so does the fast. Glucose is the only marker we sell that is invalid unfasted, so if you cannot fast, keep the early slot and take it anyway.

Venous or finger prick

Finger prick — 11 markers. Venous — 33 markers. Price and marker count both change with the option you choose above.

Bought separately, the 5 components of the finger-prick build cost £134.

Finger prick — you take it at home. No appointment and no draw fee. Collect Monday to Thursday and post the same day. Finger-prick samples fail more often than venous ones; what that means.
Venous — a professional takes the sample. You choose one of the four blood draw options in your basket, before checkout. Book Monday to Thursday and post the same day.

Before you order

• How it works — the four blood draw options, what each costs, and the process end to end.
• Choosing a test — what to check before buying any blood test, here or anywhere.
• Biomarker Guide — every marker we run, in plain English.
• Body Guide — what each organ and system actually does.

Turnaround: the lab reports this test within 24 hours of receiving your sample, counted in working days. Most samples reach them within about 3 days of posting. Full detail on our Turnaround Times page.

We do not interpret results. Not medical advice or a diagnosis.