Most finger-prick collection problems come from a small set of avoidable mistakes: cold hands, not enough blood, touching or smearing the collection card, squeezing too hard, skipping the first-drop wipe, mailing too late, or forgetting to register the kit. Here is what each mistake looks like and exactly how to get it right.
Cold hands and not enough blood
Cold fingers and dehydration are the top reasons a sample comes up short (called "Quantity Not Sufficient" or QNS).
Drink 8–16 oz of water in the 1–2 hours before you collect.
Warm your hands under warm water or hold a warm (not hot) cloth against your fingertip for at least 1–2 minutes before you prick.
Rub your hands together briskly, then let your hand hang below waist level before pricking.
If the flow slows during collection, re-warm the finger and gently massage from the base toward the tip.
Touching, smearing, or pressing the collection card
If your kit uses a collection card, the printed circles must stay completely clean and untouched.
Handle the card by its edges only — never touch the printed circles. Fingerprints contaminate the sample.
Let large drops fall freely onto each circle from above; do not press your finger against the card.
Do not wipe, smear, or layer the blood once it has landed on the card.
Squeezing too hard
Aggressively "milking" the finger pushes tissue fluid into the blood drop and dilutes the sample — even if you reach the target volume, the sample may still be unusable.
Use gentle, steady pressure from the base of the finger toward the tip.
Pause between squeezes and allow a full, round drop to build on its own before collecting it.
Not wiping away the first drop
The first drop that appears after pricking can contain tissue fluid that interferes with results. Always wipe the first drop away with the gauze from your kit before you begin collecting.
Mailing too late or on the wrong day
A sample that sits too long in transit — especially over a weekend — can degrade before it reaches the lab.
Return your sample the same day you collect it whenever possible.
Avoid mailing on a Friday or the day before a holiday.
For card kits, always let the card dry completely before sealing it for return. See the article on why drying time matters for blood cards for the timing your kit requires.
Skipping kit registration
A perfectly collected sample still cannot be processed if your kit was never registered. Registering your kit links your sample to your account and allows a physician to be assigned to review your results. Always register before you collect.
Need more help?
If your collection did not go as planned, contact our support team through chat. There is no cost for a replacement collection kit when a new sample collection is needed for the lab to complete your analysis.