CMLA Specimen Collection & Handling 2

Question 1

Which tube additive is found in a light blue (sodium citrate) tube and is used for coagulation studies?

Accepted Answer

Sodium citrate

Answer

Light blue tubes contain sodium citrate, which chelates calcium to prevent clotting and is required for coagulation tests like PT and aPTT.

Question 2

A patient's arm is edematous at the antecubital fossa. What is the most appropriate action?

Accepted Answer

Select an alternative site such as the forearm or hand

Answer

Edematous sites can dilute the specimen with fluid and alter results, so an alternative non-edematous site should be selected.

Question 3

When filling multiple tubes during a venipuncture, which tube should be filled immediately after the blood culture bottle?

Accepted Answer

Sodium citrate (light blue)

Answer

Per the CLSI order of draw, sodium citrate (light blue) tubes are filled first among additive tubes after blood cultures to avoid cross-contamination with other additives.

Question 4

How long should a tourniquet remain in place before venipuncture to avoid hemoconcentration?

Accepted Answer

No more than 1 minute

Answer

Tourniquets should be released within 1 minute to prevent hemoconcentration, which can falsely elevate cell counts and analyte concentrations.

Question 5

Which of the following is the correct angle of needle insertion for a routine adult venipuncture?

Accepted Answer

15–30 degrees

Answer

A 15–30 degree angle is standard for venipuncture, allowing the needle to enter the vein without passing through the posterior wall.

(CMLA) Certified Medical Laboratory Assistant Practice Test

(CMLA) Certified Medical Laboratory Assistant Practice Test

CMLA Specimen Collection & Handling 2