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Closure Time

Source Blood
Mnemonic CLT
Specimen Requirements

Adult:
1 x 4.5 mL blue top sodium citrate tube

Pediatric:
1 x short-draw (2.7 mL draw) blue top sodium citrate tube

Whole blood
DO NOT combine other coagulation tests on this tube.

PSC:
DO NOT collect. Refer patient to RRL Outpatient Laboratory.
(If patient is unable to go to RRL, contact Special Coagulation.)

RRL:
Collect Monday to Friday 07:00-13:00
No collections on statutory holidays

When using a winged blood collection set (butterly needle) a discard tube must be used to remove the air in the tubing, if only a citrate tube is drawn or is the first tube drawn.

Specimen Handling

DO NOT centrifuge. Indicate test clearly on specimen.

Place in individual collection bag, adhere prepared label stating "Send to DSC Special Coagulation. DO NOT CENTRIFUGE". 
Indicate STAT on specimen bag and place Stat label on transport container.

DO NOT transport samples through pneumatic tube system.

Send to Special Coagulation within 2 h of collection.
Include copy of original requisition.

Additional Information If for any reason sample must be collected after stated hours, before collecting sample, phone Special Coagulation (403-770-3598 or 403-770-3599) to ensure test can be performed.  Notify Special Coagulation before sending sample.

Hematopathologist approval is required for testing after 16:00.
Testing Location Special Coagulation
Testing Frequency Weekdays
Alternate Name(s) Replaced Bleeding time
Reference Interval 84 - 176 seconds (Collagen/Epinephrine)
63 - 111 seconds (Collagen/ADP)