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How to collect a finger-prick blood sample

Step-by-step instructions for collecting a finger-prick blood sample into a tube or card.

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Written by Riley Burcin

To collect a finger-prick blood sample, you warm your hand, prick the side of a fingertip with the lancet from your kit, and either let the blood fill a collection tube or drop onto the circles of a collection card. The exact target — a tube's fill line or the circles printed on a card — depends on your kit, so follow the markings that came with yours.

Important: Register your kit before you collect. The lab cannot process your sample until your kit is registered, and a physician cannot be assigned to review your results.

Before you start

  1. Read the instructions that came with your kit so you know whether you are filling a tube or filling circles on a card.

  2. Wash your hands with soap and warm water for at least 20 seconds, then dry them completely.

  3. Lay all kit contents out on a clean, flat surface: lancet, alcohol wipe, gauze, your collection tube or card, a bandage, the biohazard bag, and the mailer.

  4. Warm your finger by rubbing your hands together briskly for 30–60 seconds or running them under warm water. Warming your hands is the single most effective step for getting good blood flow.

Note: Many finger-prick tests require fasting and morning collection. Check your kit and see the article on preparing for your blood collection.

Collecting the sample

  1. Choose the middle or ring finger of your non-dominant hand. Avoid the thumb, index finger, and little finger.

  2. Clean the side of your fingertip with the alcohol wipe and let it air dry completely. Do not blow on it.

  3. Press the lancet firmly against the side of your fingertip (not the soft center pad) until it clicks. Each lancet is single-use only.

  4. Wipe away the first drop of blood with the gauze — it can contain tissue fluid that affects results.

  5. Let your hand hang below waist level and gently squeeze from the base of the finger toward the tip to build a large, round drop.

Then collect blood based on your kit type:

  • Tube kit: touch the blood drop to the rim of the tube and let it run in. Keep collecting drops until the tube reaches its fill line.

  • Card kit: hold your finger over a printed circle and let large drops fall freely into the center. Fill each circle with one full drop so the blood saturates the circle edge to edge. Do not touch, smear, or press your finger against the card.

  1. Pause between squeezes if the flow slows, and gently re-warm the finger if needed. Continue until your tube reaches the fill line or every circle on the card is filled.

  2. Apply gauze, then a bandage, to your fingertip.

Important: Do not squeeze the fingertip too hard. Over-squeezing dilutes the blood with tissue fluid and can make your sample unusable even if you reach the target volume.

After You collect

  1. Card kits: let the card air dry flat, away from heat and direct sunlight, before packaging. See the article on why drying time matters for blood cards for the drying time your kit requires.

  2. Tube kits: seal the tube and follow your kit's packaging steps right away.

  3. Seal your sample in the biohazard bag, complete all labels with your name, date of birth, and collection date, and return it the same day you collect.

Note: Collect on a weekday so your sample is not sitting in transit over a weekend.

Need more help?

If you cannot produce enough blood after two or three attempts, re-warm your hand and try a different finger. If you are still having trouble, or anything in your kit looks different from what is described here, contact our support team through chat. We can guide you step by step, including by photo or video. There is no cost for a replacement collection kit when a new sample collection is needed for the lab to complete your analysis.

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