Collection, Storage and Transportation of Dried Blood Spots for Infant Diagnosis

Collection, Storage and Transportation of Dried Blood

Spots for Infant Diagnosis

Learning Objectives

• Collect Dried Blood Spots (DBS) for HIV testing

• Package and store DBS so as to maintain specimen integrity

• Distinguish between valid and invalid DBS

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

Step 2

• Correctly complete all the information on the requisition form

• Keep copy for your records

Step 3

• Wash hands and dry thoroughly

• Put on gloves• Confirm identity of the infant

and write the baby’s 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 DoeMay 12th 2006

131-3347923-1-1-6

Step 4

Small infants (<9kg) 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

Choosing the site

Step 5

• 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 Do not puncture here

safe

SafeDo not puncture here

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

Step 7• Clean site with

alcohol prep• Allow to air dry for 30

seconds• Failure to allow

alcohol to dry may dilute the specimen

Step 8

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

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

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.

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

Step 12

• Fill remaining circles in the same manner with successive drops of blood

• If blood flow is diminished repeat steps 10 and 11

Step 13• Inspect card to

ensure you have collected enough blood, and the specimen is valid

Jane DoeMay 12th 2006

131-3347923-1-1-6

Valid Specimen

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.

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

Step 16 • Place dried filter

paper into Ziploc bag

• Add desiccant package

• Minimum of 2 desiccant packages per specimen

Step 17• Add humidity indicator

card • Remove air and seal

bag• Keep packaged DBS

(in sealable plastic bags) refrigerated until transported to reference laboratory

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

Step 19• During transportation

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

Invalid Specimen

• 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.

Specimen quantity insufficient for testing

Invalid Specimen

• Applying blood with a capillary tube or other device

Specimen appears scratched or abraded

Invalid Specimen

• Mailing specimen before drying for a minimum of 3 hours

Specimen not dry before mailing

Invalid Specimen

• 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

Specimen exhibits serum rings

Invalid Specimen

• 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

Specimen appears diluted, discolored or contaminated

Invalid Specimen

• Failure to obtain specimen

No blood

Invalid Specimen

• Touching the same circle on filter paper to blood several times

• Filling circle on both sides.

Specimen appears clotted or layered

Invalid Specimen

• Applying excess blood to filter paper, usually with a device

• Applying blood to both sides of filter paper.

Specimen appears super saturated