Accurate filling of specimen tube essential.
All collections that include Coagulation testing must be sent to the laboratory in a BLUE specimen bag.
If specimen cannot be sent to testing laboratory immediately, maintain specimen at room temperature.
Samples must be delivered to laboratory within 4 hrs.
Please ask the patient what anticoagulants they are on and the dose, record on request form.

Because of the D-dimer test's high sensitivity, low specificity and high negative predictive value, the best use of the test is to EXCLUDE VTE and not to CONFIRM it. In a patient with a low clinical probability of having a DVT and a NEGATIVE D-dimer test, the condition can be ruled out with a high degree of certainty. (The same does not necessarily apply for possible pulmonary embolism.) The D-dimer test may remain positive for ~2 weeks after major abdominal surgery; a positive value after 2 weeks may be suggestive of VTE in a patient with symptoms of a DVT or PE