Sign in →

Test Code LAB321 PT and PT Mixing Study

Synonym

  • PT
  • PT Mixing
  • PT Inhibitor Screen

Specimen Required

Preferred Container/Tube: 3.2% Citrate Blue Top - 2.7 mL
Specimen Volume: 2.7 mL
Acceptable Container/Tube: 3.2% Citrate Blue Top - 1.8 mL
Specimen Volume: 1.8 mL
Platelet poor plasma (PPP):
Specimen Volume: 2 - 1 mL aliquots platelet poor plasma (PPP)
Specimen Minimum Volume: 1 - 1 mL aliquot platelet poor plasma (PPP)

Specimen Collection Information

For Outreach, other than OSU Patient Service Centers: Samples must be processed and received frozen/must remain frozen in transit. 

For sending frozen plasma specimens, process immediately upon receipt. Centrifuge capped specimen tube in accordance with CLSI H21, at a speed and time required to consistently produce platelet-poor plasma (PPP = platelet count <10 K/uL). Transfer PPP into plastic aliquot tubes, cap and freeze. DO NOT transport until specimens are completely frozen.

Specimen Stability Information

Ambient: 
     Capped whole blood: 24 hours
     Capped and centrifuged: 24 hours
     Uncapped whole blood: 8 hours
     Plasma: 8 hours
Frozen: 
      Platelet poor plasma: PPP removed from the cells and frozen at -20°C or ideally -70°C.

Rejected Due To

  • Ambient capped WB specimens >24 hours old
  • Ambient uncapped WB specimens >24 hours old
  • Ambient PPP specimens >8 hours old
  • Clotted specimens
  • Underfilled or overfilled tube
  • Hemolysis

Testing Algorithm

If the PT is prolonged, then PT mixing studies will be performed at an additional charge.

Reflex Tests

Reporting Name Available Separately Always Reported
PT Mixing Studies Yes No

Reference Values

PT: 11.9-14.2 sec

INR: 0.9-1.1

Method Description

PT: Mechanical clot detection initiated by Calcium Thromboplastin

INR: Calculation

PT Mixing Study: PT performed immediately subsequent to 1:1 mix with normal plasma pool.

Performing Lab

Clinical Lab UH

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Reporting Name

PT With Mixing Study

CPT Code Information

85610
85611 (if appropriate)

LOINC Code Information

5902-2
34714-6