Beth Israel Deaconess Medical Center Laboratory Manual

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General Guidelines

• Prepare skin properly for phlebotomy (see Instructions for Performing Venipuncture ).
• Draw 5 ml of blood into a red-top tube without serum separator.
• Draw 5 – 15 ml of blood into 1-3 blue-top (citrate) tubes.
• If additional tubes are to be drawn, the order should be: green top (heparin), lavender top (EDTA), gray top (oxalate/fluoride).
• Allow tubes to fill completely. Inadequate filling will alter the intended ratio of blood to anticoagulant (approximately 9:1) and cause inaccurate results and canceling of testing by the lab.
• If using a syringe, it is preferable to perform venipuncture with a "butterfly" so that at least 5 ml of blood can be withdrawn and discarded. Change to a second syringe to then withdraw the coagulation specimen. DO NOT inject into evacuated blue top tubes using a needle. Rather, uncap the tubes to release the vacuum and slowly allow the blood from the syringe to run down the side of the tubes. Do not squirt the blood into the tube!
• Immediately and gently invert tubes several times to insure proper mixing with the anticoagulant. Avoid foaming.
• Immediately transport the specimen to the laboratory. Clotting factors decrease over time.
• Specimens sent to the lab immediately by pneumatic tube do not need to be on ice.

Newborns or adult patients with hematocrits >55%

• Call the laboratory prior to phlebotomy so that a tube can be prepared with an appropriate volume of citrate. Overfilling or underfilling a tube will make the specimen unacceptable for accurate testing.

Patients with indwelling lines that are being flushed with heparin

• It is best to draw a specimen peripherally and not through the line.
• If it is necessary to draw through the line:
• Flush the line with saline. Draw off at least 5 ml of blood and discard.
• Obtain specimen for coagulation studies as described above.
• On the requisition slip note that the specimen was drawn through a heparinized line

COAGULATION TESTING AVAILABLE OFF-HOURS

(Weekends, holidays and 5 PM to 7 AM weekdays)

PT
PTT
Thrombin Time
Platelet count
Fibrinogen
D-dimer
FDP
LMWH levels (anti-Xa activity)  - only if requested STAT
Factor VIII level (only on special request; MD must call the laboratory prior to sending the specimen)

 Reviewed/revised 1/15/2008