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An Overview of Dried Blood Spot Testing

Learn about the reliability and accuracy of blood spot collection.
An Overview of Dried Blood Spot Testing

Dried blood spot collection offers a simple solution for collecting, preserving, and transporting blood samples. At-home testing using dried blood spot collection eliminates the need for venipuncture blood draw in a lab and allows convenience by taking your sample from the comfort of your own home. 

Often, we see questions about the reliability or accuracy of these tests.

History of blood spot collection

Dried blood spot testing has been around for decades.

In 1913, physician Ivar Bang introduced the idea of using dried blood as a sampling method. The idea was actualized in 1963 by microbiologist Robert Guthrie. Guthrie initially wanted to screen intellectually disabled children using this approach, which gave way to the introduction of newborn screening for inherited metabolic disorders.

The limitations of sensitivity and specificity when screening such small sample volumes of blood restricted the use of dried blood spots for many years. As mass spectrometry (an analytical technique that measures the mass-to-charge ratio of ions) expanded into clinical laboratories, the applications of blood spot collection grew, too.

Today, this method tests hundreds of biological markers successfully.

How dried blood spot collection works

Draw dried blood spot samples using a finger-prick via a small lancet. A few droplets of blood are then dropped drop onto specially manufactured absorbent filter paper. 

The Clinical and Laboratory Standards Institute recommends the use of two specific collection cards: the Whatman 903 and Ahlstrom 226. These two collection cards are both approved by the Food and Drug Administration, Newborn Screening Quality Assurance Program, and the Centers for Disease Control and Prevention.

The blood is allowed to saturate the paper thoroughly and air-dries for at least 30 minutes. Once dry, these cards are stable for shipment and storage

While samples do not need to be specifically temperature regulated, it’s advisable to store the collection card in a cool place and ship to the laboratory as soon as possible.

How to take your sample

Important reminders

  • Do wash your hands with warm water and dry with a clean towel before handling the kit contents
  • Do rub your hands together, swing your arms, or gently massage your forearm to encourage blood flow before nicking your finger

  • Do NOT touch the blood collection area within the marked circles on the blood collection card
  • Do NOT overlap blood drops on the same spot
  • Do NOT reuse lancets provided in the kit

How to collect a sample

  1. Watch blood collection instructional video.
  2. Wash your hands under warm water and dry with a clean towel.
  3. Verify the kit contents and arrange them on a flat surface - preferably below your waist level.
  4. Write your name and collection date on the card in the provided space.
  5. Use an alcohol wipe to clean the outer edge of your middle or ring finger of your non-dominant hand. Let dry for 30 seconds.
  6. Twist cap off the provided lancet and press the lancet firmly against the outer edge of your fingertip until you hear the lancet click. (Blue lancets are activated on contact when pressed down. Yellow lancets are activated by pushing down the button at the top.)
  7. Wipe away the first drop of blood with a sterile gauze pad.
  8. Position finger over the printed circle of blood spot card and gently massage the entire finger to form a large, hanging blood drop.
  9. Touch the hanging blood drop to the center of the circle without touching your finger to the paper. Remember - one drop per circle and do not overlap blood-drops!
  10. Continue blood collection until you fill all the circles. If you cannot get enough blood, repeat from step 2 using a different finger and the second lancet provided.
  11. Once finished, gentle press the gauze pad against the finger to stop the bleeding and apply a bandaid.
  12. Leave the blood spot card open to dry for at least 30 minutes. 
  13. After drying, close the top flap and place the card into the plastic pouch and seal.

A note from Paloma Health

It's good to note that reference ranges vary by lab, meaning that different labs may yield different results. That is normal. Variability can occur due to differences in testing equipment, chemicals used, and analysis techniques. This variability is the reason you should use the range supplied by the lab that analyzed your test to evaluate whether your results are within normal limits. We recommend you use the same laboratory each time you have your labs drawn. 

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