- Slides: 30
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 Jane Doe May 12 th 2006 131 -3347923 -1 -1 -6 • 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
Step 4 Choosing the site § Small infants (<9 kg) § § § Puncture the heel. Do not puncture the fingers; there is risk of hitting the bone. Larger infants (> 9 kg) § § § 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
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 4 th and 5 th 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
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 410 c 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 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 Jane Doe May 12 th 2006 • Inspect card to ensure you have collected enough blood, and the specimen is valid 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 quantity insufficient for testing • • 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.
Invalid Specimen appears scratched or abraded • Applying blood with a capillary tube or other device
Invalid Specimen not dry before mailing • Mailing specimen before drying for a minimum of 3 hours
Invalid Specimen exhibits serum rings • 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
Invalid Specimen appears diluted, discolored or contaminated • 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
Invalid Specimen No blood • Failure to obtain specimen
Invalid Specimen appears clotted or layered • Touching the same circle on filter paper to blood several times • Filling circle on both sides.
Invalid Specimen appears super saturated • • Applying excess blood to filter paper, usually with a device Applying blood to both sides of filter paper.