Page 186 - pathology_services_handbook_5th_edition_2018

4.5 Procedure for Collection of Dried Blood Spot on Whatmann Filter Paper

A) Filter Paper
HTAA, KUANTAN Whatmann 903 filter paper is required which has special thickness and is manufactured

solely for blood collection.

B) Time of Collection

Timing of collection is critical. It is recommended that the DBS sample for Newborn
Screening of IEM be collected from already fed baby at the age between 48-72 hours.
If a baby is to be discharged before 48 hours of age, blood can still be collected but
a repeat sample at >48-72 hours may be required. This allows for early metabolic
changes and the commencement of milk and protein feeds.

Samples collected too early may give false negative results. Samples collected too late
may place children with health problems at risk of irrevirsible damage.

C) Procedures

i) Making DBS from Heel-prick or Finger-prick

For normal newborn baby without any symptoms, it is advisable to collect blood from
heel-prick.
1. Label each card with baby’s identifications and date of collection and any other
pertinent information.
2. Wear gloves and warm the foot with warm cloth/ towel.
3. Clean the side area with either alcohol swab then dry with a clean gauze or
cotton wool swab.
4. Puncture heel with sterile lancet (point <2.4 um) on medial or lateral plantar
surface.
5. Allow puncture to ooze and wipe away first drop of blood with cotton swab.
6. Gently massage above the puncture to encourage blood flow and drop a big
spot of blood onto each of the 3 circles on the filter paper.
7. Continue step (5) and (6) until all the circles are filled. One full drop of blood
equivalent to 50ul is required to fill each circle. Blood must soak through the
card to the other side. Do not drop more than one drop of blood on one circle.
8. Completely dry the card at room temperature (25 C to 30 C) on a clean, flat,
o
o
non-absorbent surface or a drying rack designed for the purpose, for more than
4 hours or overnight. Minimum time needed for drying is 4 hours.
9. To avoid contamination of the sample, do not touch the blood spot circle with
bare hand.

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