Collection, Storage and Transportation of Dry Blood Spots DBS for Infant Diagnosis

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Collection, Storage and Transportation of Dry
Blood Spots (DBS) for Infant Diagnosis

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Objectives

• This presentation will teach you how to
• Collect Dried Blood Spots (DBS) for HIV testing
• Package and store DBS so as to maintain specimen
  integrity
• Distinguish between valid and invalid DBS samples

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Step 1

• Equipment
• DBS sample collection card
• DBS Lab requisition Form
• Sterile lancet
• Sterile alcohol prep
• Sterile gauze/cotton swab
• Gloves
• Drying rack
• Low Gas Permeable zip-lock bag
• Desiccant
• Humidity indicator card

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Step 2

• Correctly complete all the information on the
  requisition form
• Keep copy for your records

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Step 3

• Wash hands and dry thoroughly
• Put on gloves
• Confirm identity of the infant and write the
  babys name, date of the test and the unique
  identifier on the filter paper
• Do no not contaminate by touching or allowing
  spillage on the filter paper

Jane Doe
August 13th 2006
131-3347923-1-1-6
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Step 4
Choosing the site

• Small infants (
• Puncture the heel.
• Do not puncture the fingers there is risk of
  hitting the bone.
• Larger infants ( 9kg)
• Puncture the heel if callous is visible, you may
  use the lateral aspect of the big toe.
• Do not stick the fingers or small toes there is
  risk of hitting the bone.
• Fingers are safe in children 2 years of age

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Step 5
Do not puncture here
Safe

• Draw an imaginary line from midpoint of the big
  toe to the heel and one from between the 4th and
  5th toe to the heel.
• Shaded area indicates safe areas for puncture
  site
• Do not puncture the back of the heel or Achilles
  tendon or the medial aspect of the big toe

safe
safe
Do not puncture here
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Step 6

• Position baby with foot down
• This will help the blood flow more easily
• Warm site with soft cloth moistened with warm
  water up to 410c for 3 to 5 minutes

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Step 7

• Clean site with alcohol prep
• Allow to air dry for 30 seconds
• Failure to allow alcohol to dry may dilute the
  specimen

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Step 8

• Puncture the toe to a depth less than 2 mm using
  a sterile lancet

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Step 9

• Wipe away first blood with sterile gauze pad
• The initial drop contains tissue fluid that may
  dilute the specimen
• Allow another large blood drop to form

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Step 10

• Lightly touch the filter paper to the large drop
  of blood
• Allow to soak through and completely fill the
  circle
• To enhance flow very gently apply intermittent
  pressure to area above the puncture site.

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Step 11

• Apply blood to one side of the filter paper only,
  the side with the printing
• Do not layer successive drops of blood or apply
  blood more than once to the same collection
  circle
• Avoid touching or smearing the spots

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Step 12

• Fill remaining circles in the same manner with
  successive drops of blood
• If blood flow is diminished repeat steps 10 and 11

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Step 13

• Inspect card to ensure you have collected enough
  blood, and the specimen is valid

Jane Doe
August 13th 2006
131-3347923-1-1-6
Valid Specimen
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Step 14

• Place filter paper on a horizontal clean dry
  surface to AIR DRY for at least 3 hours
• Keep away from direct sunlight, dust, and bugs
• Do not allow blood spots to come into contact
  with any surface or each other.

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Step 15

• Place dried DBS cards between sheets of glassine
  paper so that the DBS cards are not touching each
  other
• Fold ends of the glassine paper

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Step 16

• Place dried filter paper into Ziploc bag
• Add desiccant package
• Minimum of 2 desiccant packages per specimen

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Step 17

• Add humidity indicator card
• Remove air and seal bag
• Keep packaged DBS (in sealable plastic bags) in a
  drawer until transported to reference laboratory

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Step 18

• Transportation
• Place bag into envelope
• Add lab requisition slips and specimen delivery
  check list
• Clearly label outside of the envelope
• Transport to central laboratory for processing

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Step 19

• During transportation do not leave in vehicle, as
  sun and heat will deteriorate DBS

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Invalid Specimen
Specimen quantity insufficient for testing

• What might cause this?
• Removing filter paper before blood has completely
  filled circle or before blood has soaked through
  to second side.
• Applying blood to filter paper with a capillary
  tube
• Touching the filter paper before or after
  specimen collection with a gloved or ungloved
  hands, hand lotion etc.
• Allowing the filter paper to come into contact
  with gloved or ungloved hands or stances such as
  hand lotion or powder, either before or after
  blood specimen collection

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Invalid Specimen
Specimen appears scratched or abraded

• What might cause this?
• Applying blood with a capillary tube or other
  device

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Invalid Specimen
Specimen not dry before mailing

• What might cause this?
• Mailing specimen before drying for a minimum of 3
  hours

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Invalid Specimen
Specimen exhibits serum rings

• What might cause this?
• Not wiping alcohol from puncture site
• Allowing filter paper to come into contact with
  alcohol , hand lotion etc.
• Squeezing area surrounding puncture site
  excessively
• Drying specimen improperly
• Applying blood to filter paper with capillary tube

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Invalid Specimen
Specimen appears diluted, discolored or
contaminated

• What might cause this?
• Squeezing or milking of area surrounding
  puncture site
• Allowing filter paper to come into contact with
  gloved or ungloved hands or substances such as
  alcohol, formula, antiseptic, water, powder etc.
  before or after blood specimen collection
• Exposing blood spots to direct heat

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Invalid Specimen
No blood

• What might cause this?
• Failure to obtain specimen
• Card mix-up

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Invalid Specimen
Specimen appears clotted or layered

• What might cause this?
• Touching the same circle on filter paper to blood
  several times
• Filling circle on both sides

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Invalid Specimen
Specimen appears super saturated

• What might cause this?
• Applying excess blood to filter paper, usually
  with a device
• Applying blood to both sides of filter paper

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Summary

• DBS samples are easy to collect, package, and
  store if specific procedures are followed
• The appearance of the DBS can suggest whether or
  not the sample is valid