Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
INR is the accepted method for controlling Vitamin K antagonist anticoagulant therapy (primarily Warfarin). The patients Prothrombin Time (PT) is divided by the laboratory Mean Normal Prothrombin Time (MNPT) and the resulting ratio is then raised to the power of the ISI, to convert results to a common WHO standard. However, for patients on Warfarin and a direct oral anticoagulant (DOAC), such as Bivalirudin, patient plasma must be pre-treated with DOAC-RemoveTM to remove the DOAC before an INR can be performed to obtain reliable results.
Specimen container paediatric:
Light blue – sodium citrate
Specimen container adult:
Light blue – sodium citrate
Minimum volume paediatric:
1.3ml
Minimum volume adult:
2.7ml
Special requirements:
Tube must be correctly filled to line, to ensure correct ratio of blood to anticoagulant, ensure adequate mixing.
Sample stability:
24 Hours
Transport requirements:
Samples should be transported to lab without delay
Freq analysis:
As required or weekly
Add on test:
[email protected] (external)
Quality assurance:
UK NEQAS Blood Coagulation
Reference ranges:
1.5 – 4.0. Dependent upon specific target value for patient.
Other info:
To monitor warfarin like anticoagulants when patient also on DOAC