Good preparation makes a finger-prick blood collection faster, easier, and more accurate. The four things that matter most are hydration, warm hands, following any fasting instructions for your test, and collecting at the right time of day. Always check your kit's printed instructions, because requirements vary by test.

Drink 8–24 oz (one to three glasses) of water in the 1–2 hours before you collect. Dehydration is the most common reason a finger-prick collection does not produce enough blood. Water is allowed even when you are fasting, so stay hydrated.

Warm hands produce better blood flow than cold ones. Right before you start:

Some tests — such as cholesterol, glucose, and certain hormone panels — require fasting before collection. If your kit says to fast:

Important: If you take biotin (vitamin B7), your kit may ask you to stop it for a period before collecting because biotin can interfere with some test results. Follow your kit's specific timing. Never stop a prescribed medication without first talking to your care provider.

Most finger-prick tests are best collected in the morning before eating. Many tests should also be collected on a weekday so your sample is not held in transit over a weekend.

Plan to collect and return your sample on the same day. Check your kit for any test-specific timing, such as collecting before breakfast or within a certain hour after waking.

If you are not sure whether your test requires fasting or a specific collection time, contact our support team through chat with your Kit ID and we will confirm the requirements for your specific test.