Test Code Billings Clinic: 2042 Protime (PT), Dialysis, Plasma

Important Note

Billings Clinic Dialysis Patients Only

Billings Clinic Laboratory: Coagulation

Used to screen for hemostatic disorders involving fibrin formation and to monitor the effectiveness of oral anticoagulant therapy.

Optical

See “Coagulation Studies—Billings Clinic Laboratory” under Resources

Draw blood in a light blue-top (3.2% sodium citrate) tube.
Immediately after draw, gently invert tube(s) at least 6 times to mix well.
Spin down, remove plasma, spin plasma again, and place 1 mL of citrate platelet-poor plasma in plastic vial.
Glass vial is not acceptable.
Double-centrifuged specimens are critical for accurate results as platelet contamination may cause spurious results.
Freeze specimen immediately at -20° C.
Send specimen frozen.

Protime:

Call-back value: ≥43 seconds

INR:
2-3 (only for patients on oral anticoagulation)
Call-back value: ≥4.5

Reference values change with each new reagent lot (about once a year). Check with laboratory or refer to reference range on computer reports.

85610 - Prothrombin time