Page 187 - pathology_services_handbook_5th_edition_2018

10. Place dried filter paper in an individual plastic bag for transport. It is
recommended that the filter paper (dried blood spot) is store away from any
source of heat, liquid and organic fumes.

ii) Making DBS from Blood Collected from Venepuncture

1. Label each card with patient reference, sample collection date and any other CHEMICAL PATHOLOGY
pertient information.
2. Collect blood in heparinised tube (green top). If blood is drawn in a syringe,
transfer it into a green tube.
3. Set a hand-held pipettor to 50uL volume and fill the pipette tip with blood. (If
the tube has been sitting still for more than 2 minutes, it must be mixed by
inverting it up and down few times before pipetting).
4. Follow Procedure (8)-(10) as in C.i) Making DBS from Heel-prick or Finger-prick.

Notes:
The filter paper card(s) must be completely dry before dispatch. Protect them from
moisture or condensation at all times.
Store at 4 C if the card is transported the next day after it is dried. Freeze at -20 C for
o
o
long-term storage.
The DBS must be prepared at least 4 hours ahead of transportation to allow complete
drying.

D) Quality of DBS
i) Acceptable Blood Sample Cards

Each blood spot is checked for acceptability. Blood spot should be dry, the pre-printed
circles filled and appear as an even dark colour on both sides of the card without lighter
discolouration.

ii) Rejection Criterias
Unsuitable DBS will be rejected such as follows:

1. Lack of blood coverage (Quantity insufficient for testing - Blood spot’s diameter
is too small)
2. Layering of blood
3. Incomplete blood saturation
4. Separation of red blood cells and serum
5. Blood spot contaminated with fungus
6. Blood spot is diluted/ contaminated with water

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