Test Your Guthrie Knowledge

CONCEPT: History of PKU



Review the history of the Guthrie card and learn how to collect a Guthrie sample, including the steps involved, supplies needed, and hints for success.



After completing this activity, children will be able to:

  • name at least one reason to collect a Guthrie blood sample
  • identify the correct steps for collecting a Guthrie sample
  • list the supplies needed for a Guthrie sample
  • identify what a valid blood specimen looks like (when compared to an invalid specimen)



Open the discussion by showing children the Guthrie card. Lead a discussion:

  • Why is it called a Guthrie card? ( It's named after Dr. Guthrie, who developed this newborn screening test for PKU in 1962.)
  • Why do we collect a blood sample on the Guthrie card? (to measure our blood phe level)
  • When should a Guthrie blood sample be collected? (when your blood phe level at last clinic visit or last Guthrie was greater than 10 mg% or less than 1 mg%, your phe prescription has been changed, you have had a significant illness, or you missed clinic and did not have your blood phe test during the month)
  • Review the hints to help make the blood draw successful (these can be found in the Monitoring Blood Phenyalalnine Levels at Home brochure below.)
  • Review the "Steps in Collecting a Guthrie Sample". (Pass out this handout to the children.) The steps include:
    1. Fill out filter paper with your name, birthdate, and draw date.
    2. Warm finger or hand.
    3. Wipe skin with alcohol swab.
    4. Use lancet for the "poke".
    5. Fill 2 circles with blood.
    6. Allow filter paper to air dry.
    7. Put filter paper in the envelope.
    8. Mail sample to the lab.
  • Review the examples of unacceptable/invalid specimens on the "Simple Spot Check" poster

Distribute the worksheet to the children. Allow time for them to answer the questions independently. Discuss the answers together.
(Answers: Part 1: 6,1,5,8,7,4,3,2; Part 2: no need to go to the lab--no appointment needed, it's cheaper, you can do it right away; Part 3: F, T, T, F, F, F; Part 4: lancet, filter paper, alcohol swab, band aid, pen)

Optional: Do Your Own Finger Poke
If you are at a facility where you can accomodate this, encourage the children to do their own finger poke (with the appropriate assistance available), so they can practice what they learned.

Give families a copy of the brochure Monitoring Your Blood Phenylalanine Levels at Home to take home with them for reference later. The article Tips for Dealing with Blood Draws at Different Ages is also very helpful for parents.



  • Guthrie card
  • acrobat reader logo Steps in Collecting a Guthrie Sample
  • acrobat reader logo Worksheet
  • Pencils
  • acrobat reader logo Simple Spot Check poster
  • acrobat reader logo Monitoring Blood Phenylalanine Levels at Home (to send home with families)
  • Article for parents: Tips for Dealing with Blood Draws at Different Ages, by Deborah Padgett, in National PKU News 1991;3:1:4-5.
  • If you will be doing finger pokes, you will need: Guthrie filter paper, lancets, alcohol swabs, bandaids, pens


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