Mixing Study

Overview

  • EPIC Code:
  • LAB2444
  • Soft Test Code:
  • MIXS1
Alternate Names
  • Circulating Anticoagulant
  • Mixing Studies
Clinical Significance

A mixing study aids in differentiating the cause of a prolonged prothrombin time (PT) and/or prolonged activated partial thromboplastin time (APTT).


Specimen Collection & Preparation

Client Notes

Contact Client Response at 266-1500 (Option 2) for Stat Courier


Specimen Requirements:

-OR-

2.7 mL Whole Blood in TWO Full Blue Top Tubes - 3.2% Buffered Sodium Citrate
Minimum Volume:
3.0 mL Citrated Plasma*

* This volume does not allow for repeat testing

Collection Instructions:

Specimens must NOT be collected from indwelling lines or ports.

Correct ratio of Blood to Citrate is critical (9:1). Specimens must be filled within +/- 10% of stated volume.

Mixing Study Medication Screen must be completed at the time of specimen collection.


Rejection Criteria:

Clotted samples

Improperly filled tubes (under or overfilled)

Wrong anticoagulant (3.8% sodium citrate is NOT acceptable)

Patients with hematocrit (HCT) >55% (red cell volume is >1/2 tube volume)

Hemolyzed samples

Whole blood samples received on ice or refrigerated

Improperly labeled specimens

If heparin, low molecular weight heparin, direct thrombin inhibitor or warfarin are present


Transport and Storage:
  • Ambient (18-24°C): 4 Hours

    Specimens stored at room temperature must have all mixing study testing completed within 4 hours of collection.

  • Frozen (-20° C or colder): 2 Weeks

    If testing cannot be performed immediately, platelet poor plasma may be frozen at -20°C or colder within 2 hours of collection.

    Do not freeze in frost-free freezer.

The preferred specimen is whole blood specimen stored at room temperature and received at the testing site (PRMC) within 2 hours of collection.

Clinical Interpretation

Reference Range:

Refer to Interpretive Pathology Report


Methodology:
  • Optical
Clinical Significance

A mixing study aids in differentiating the cause of a prolonged prothrombin time (PT) and/or prolonged activated partial thromboplastin time (APTT).


Documentation

PT and APTT will be performed at time of collection. If the prolongation of the PT and APTT is less than 2 seconds and 5 seconds over the respective reference ranges, the mixing study will not be performed per established criteria of Parkview Laboratories.


Production Schedule

Sites Performed
  • Parkview Regional Medical Center
Days Performed
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Departments
  • Coagulation
Turn Around Time

1 to 4 days


Coding & Compliance

CDM

01421001, 01421003, 01421000, 01450039, 01450046


CPT Coding

85732 x 2, 85611, 85610, 85730