Prothrombin Time with INR Collections

Supply #T04 - Light Blue 2.7mL

Test code: 8847

Methodology: Photo-optical Clot Detection

Clinical Significance: Screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders.

Test FAQ: Prothrombin Time with INR

Alternative Name(s): PT

Collection Guide: 

Supply: T04 - Light Blue 2.7mL

Preferred Specimen: One Full Unopened 3.2% Sodium Citrate (Light Blue-Top) Tube


A completely filled tube is necessary because the correct ratio of blood to citrate is critical (9:1). Mix by gentle inversion 3-4 times. Do not uncap.

Instructions: a completely filled tube is necessary because the correct ratio of blood to citrate is critical (9:1). Mix by gentle inversion 3-4 times. Do not uncap. Minimum Volume Ratio of blood to citrate is critical. Submit difficult draws in pediatric (light blue-top) tube.

Coagulation specimen collection requirements:

A light-blue top tube (containing 3.2% sodium citrate) that will be used for coagulation testing must be filled to completion. Please see the attached BD guides for instructions. Under-filling the tube changes the ratio of blood to anticoagulant additive. The under-filled tube will be considered an improper specimen.

Specimen must reach the band etched into the tube – it is critical that that band is reached by the specimen. The position of the label and any markings on it are immaterial – that etched band is the goal.

If a winged blood collection device (butterfly) is used to collect a light-blue top tube for coagulation studies, a waste tube must be drawn first. The waste tube must also be a light-blue top tube or a tube that contains no additives. This waste tube is drawn first to remove the air in the tubing of the winged collection device. Once blood flows through the tubing, the waste tube can be removed and discarded. The waste tube does not need to be completely filled. If the air is not displaced from the tubing into a waste tube, it will be drawn into the specimen tube and cause a short-fill of the tube. Less volume of blood in the tube alters the required blood-to-anticoagulant ratio needed for coagulation studies. The under-filled tube will be considered an improper specimen.

Expired tubes lose their vacuum and will not pull enough blood into the tube for the correct blood-to-anticoagulant ration. The under-filled tube will be considered an improper specimen.

Transport Container: 3.2% Sodium Citrate (Light Blue-Top) Tube

Transport Temperature: Room Temperature

Specimen Stability:
Unopened Light Blue-Top Tube
  • Room Temperature: 48 Hours
Reject Criteria:
  • Improper Blood To Citrate Ratio
  • High Hematocrit
  • Improper Blood Collection

For additional supply or collection device information, please contact DLO's Customer Service at (800) 891-2917, option 2.