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Test Code LAB326 PTT with Mixing Study

Synonym

  • PTTMS
  • PTT/Mixing
  • aPTT/Mixing
  • PTT 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: 
     Whole blood: 1 hour
     Capped and centrifuged: 4 hours
     Centrifuged and plasma separated from cells: 4 hours
      Platelet poor plasma: 4 hours
Frozen: 
      Platelet poor plasma: PPP removed from the cells and frozen at -20°C or ideally -70°C.

Rejected Due To

  • Ambient WB specimens > 1 hour old
  • Ambient PPP specimens >4 hours old
  • Clotted specimens
  • Underfilled or overfilled tube
  • Hemolysis

Testing Algorithm

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

Reflex Tests

Reporting Name Available Separately Always Reported
PTT Mixing Studies Yes No

Reference Values

24.0-34.3 sec

Method Description

PTT Mixing Study: PTT 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

PTT With Mixing Study

CPT Code Information

85730
85732 (if appropriate)

LOINC Code Information

14979-9