Specimen Requirements

Specimen Type

Whole Blood Sodium Citrate

Specimen Required 

Container/Tube: 2 Blue Tops

Specimen Volume: Tubes must be filled to etched line to ensure appropriate anticoagulant to blood ratio.

Collection instructions: 

1. Prepare the arm for normal phlebotomy using alcohol sponge and sterile gauze.

Apply tourniquet and make a clean venipuncture using a 19 - 21G butterfly needle.

Discard the first 3-5 ml, which contains tissue contaminants (can be used for other,

non-coagulation testing). Attach a clean plastic syringe and gently draw 6 ml of

blood and transfer it to 2 blue-capped tubes containing 0.5 ml of 3.2% (0.105 M)

sodium citrate (pH7.4). Cap and mix blood with the citrate by gentle inversion 5-7

times in order to mix well but not activate clotting factors. Do not mix again until

ready to assay.

2. Collection of citrated whole blood from indwelling venous blood line.

a. Do not obtain blood from a heparinized access line, lock, or indwelling heparin lock.

b. Discontinue fluid drip, if required.

c. Draw 10 cc of blood with one syringe – discard.

d. Attach a clean plastic syringe and gently draw 6 ml of

blood and transfer it to 2 blue-capped tubes containing 0.5 ml of 3.2% (0.105 M)

sodium citrate (pH 7.4). Cap and mix blood with the citrate by gentle inversion 5-7

times in order to mix well but not activate clotting factors. Do not mix again until

ready to assay.