Inhibitor Assay, PTT with Reflex to PTT 1:1 Mix, with Reflex to 1-Hour Incubation
Ordering Recommendation
Electromagnetic Mechanical Clot Detection
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Lt. blue (sodium citrate). Refer to Specimen Handling at for hemostasis/thrombosis specimen handling guidelines.  
Specimen Preparation
Transfer 2 mL plasma to an ARUP Standard Transport Tube. (Min: 1 mL)  
Storage/Transport Temperature
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.  
Unacceptable Conditions
Serum. Specimens refrigerated more than four hours. Hemolyzed specimens.  
Ambient: 4 hours; Refrigerated: 4 hours; Frozen: 2 weeks  
Reference Interval
Test Number Components Reference Interval
Partial Thromboplastin Time 32-​48 seconds
2003270Partial Thromboplastin Time 1:1 Mix (performed if PTT > 48 seconds) 32-​48 seconds
2003272Partial Thromboplastin Time 1 hour By report
Partial Thromboplastin Time Inhibitor Screen 1 Hour, Mix By report
Interpretive Data
If PTT is prolonged, a PTT 1:1 immediate mixing study will be added. If the immediate mixing study is normal, an incubated mixing study will be added. Additional charges apply.
CPT Code(s)
85730; if reflexed, add 85732; if reflexed add 85730; 85732
Component Test Code*Component Chart Name
2003267PTT, Inhibitor Screen
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, contact interface support at
Cross References
  • Partial Thromboplastin Time
  • Partial Thromboplastin Time 1:1
  • Partial Thromboplastin Time Inhibitor Assay
  • Partial Thromboplastin Time Mixing Study
  • PTT
  • PTT 1:1 Mix
  • PTT Inhibitor Assay
  • PTT Mixing Study