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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 thyroid blood sample from the comfort of your own home.
Often, we see questions about the reliability or accuracy of these tests.
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 use this approach for the assessment of children with intellectual disabilities, which gave way to the introduction of newborn screening tests 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.
Draw dried blood spot samples using a finger-prick via a small lancet. A few drops 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 it to the laboratory as soon as possible.
Taking a hypothyroidism test at home is easy. The at-home thyroid test kit comes with everything you need for sample collection and blood spot analysis of TSH, free T3, free T4, and TPO antibodies with the option to add on reverse T3 and/or vitamin D.
The kit is sent directly to your address, requires an easy finger prick, and then is sent back to the lab, with pre-paid shipping both ways. Your thyroid lab results are released to your secure online dashboard within days, similar to the wait time for in-person lab results without the inconvenience.
- 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 drops of blood on the same spot
- Do NOT reuse lancets provided in the kit
How to collect a sample
- Watch the blood collection instructional video.
- Wash your hands under warm water and dry with a clean towel.
- Verify the kit contents and arrange them on a flat surface - preferably below your waist level.
- Write your name and collection date on the card in the provided space.
- Use an alcohol wipe to clean the outer edge of the middle or ring finger of your non-dominant hand. Let dry for 30 seconds.
- Twist the 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.)
- Wipe away the first drop of blood with a sterile gauze pad.
- Position the finger over the printed circle of the blood spot card and gently massage the entire finger to form a large, hanging blood drop.
- 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!
- Continue blood collection until you fill all the circles. If you cannot get enough blood, repeat step 2 using a different finger and the second lancet provided.
- Once finished, gently press the gauze pad against the finger to stop the bleeding and apply a bandaid.
- Leave the blood spot card open to dry for at least 30 minutes.
- 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.I