Hong Kong Children''s Hospital

Newborn Screening Laboratory

Instructions for Collection of Dried Blood Spots

1. Prepare the dried blood spots collection card and blood collection accessories. Do not touch the circles.
2. Critical samples collected during metabolic decompensation or symptomatic phase are usually more informative. Otherwise, blood samples should be collected preferably before meal or 2 hours after meal and at least 24 hours after birth for newborns with normal commencement of milk feeding.
3. Stick the GUM label of the patient on the DBS card.
4. A. From Back of Hand. Ensure the hand is warm with good circulation. Swab the hand with alcohol pad and allow air-dry. Make the venipuncture with a sterile needle. Allow a drop of blood to form that will be large enough to fill the circle. Collect the blood on one side of the card directly. Make sure that the blood fills the circle completely and saturates the cards. Repeat to fill all circles one by one. B. Syringe. If other specimens are to be collected at the same time, collect the blood with a syringe. Remove the needle and collect the blood on one side of the card directly. Repeat to fill all circles one by one. Make sure that the blood fills the circle completely and saturates the card. Continue to fill other specimen tubes. C. Heel prick. Ensure the heel is warm with good circulation. Swab the heel with alcohol pad and allow air-dry. Within the shaded area as shown below, make the puncture with a sterile lancet to a depth not greater than 2 mm. Gently wipe away the first drop of blood with sterile gauze. Do not squeeze the foot. Allow a drop of blood to form that will be large enough to fill the circle. Collect the blood on one side of the card directly. Make sure that the blood fills the circle completely and saturates the paper. Repeat to fill all circles one by one.
5. Place the DBS card horizontally and allow air-dry for at least three hours. Avoid stacking, touching other surfaces, direct sunlight or direct heating. Put the dried DBS card into a specimen bag and send to Newborn Screening Laboratory, 7/F, Tower A, Hong Kong Children’s Hospital.

• Valid specimens: both sides of the spot should look the same


• Invalid specimens:
  • Specimen quantity insufficient for testing (reason: too early removal of card from blood)
  • Specimen appears scratched or abraded (reason: damage during collection using capillary tube)
  • Specimen not dried before mailing (reason: insufficient or inappropriate drying)
  • Specimen appears diluted, discolored or contaminated (reasons: contamination by hand or glove etc; direct heating or sunlight exposure; excessive squeezing surrounding the puncture site or alcohol contamination)
  • Specimen exhibits serum rings (reasons: excessive squeezing surrounding the puncture site or alcohol contamination; contamination by hand or glove etc. insufficient or inappropriate drying)
  • Specimen appears layered (reasons: applying blood onto both sides of card, repeatedly applying blood to same position)
  • Specimen appears clotted (reasons: applying blood onto both sides of card, repeatedly applying blood to same position)
  • Specimen appears super saturated (reasons: applying blood onto both sides of card, repeatedly applying blood to same position)
  • Specimen diffuses to the cover of the dried blood spot card (reasons: the flap of the cover overlaps with the surface of sampling card during sample collection, insufficient or inappropriate drying)
  • No blood (reason: failure to collect blood)
  • Specimen appears multi-spotted (reason: expel the blood from capillary tube in multiple action)