Phlebotomy Test Capillary and Dermal Puncture

Question 1

When performing a fingerstick on an adult patient, which finger is the PREFERRED site?

Accepted Answer

Middle or ring finger

Answer

The middle (third) and ring (fourth) fingers are preferred for adult fingersticks because they have adequate tissue depth and fewer nerve endings than the index finger.

Question 2

Why is the first drop of blood wiped away during a capillary puncture?

Accepted Answer

To remove tissue fluid that could dilute or contaminate the sample

Answer

The first drop contains tissue fluid released when the skin is punctured, which dilutes the blood sample and can alter test results; it must be discarded.

Question 3

The correct order of draw for capillary specimens collected in micro-collection tubes is:

Accepted Answer

Blood gases → EDTA → other additive tubes → serum tube

Answer

Capillary order of draw begins with blood gas specimens (if collected), then EDTA (lavender/pink) first to ensure accurate hematology results, then other additive tubes, then serum tubes last.

Question 4

What is the maximum recommended depth of a heel puncture in a full-term neonate?

Accepted Answer

2.0 mm

Answer

CLSI recommends a maximum lancet depth of 2.0 mm for full-term neonates to avoid penetrating the calcaneus (heel bone) and causing osteomyelitis.

Question 5

Which area of the neonatal heel is the CORRECT site for a heelstick?

Accepted Answer

Medial or lateral plantar surface of the heel

Answer

CLSI guidelines specify the medial or lateral plantar surface of the heel as safe sites, avoiding the posterior curve and center where the calcaneus is close to the surface.

Phlebotomy Practice Test Practice Test

Phlebotomy Practice Test Practice Test

Phlebotomy Test Capillary and Dermal Puncture