Lab Test

Hexagonal Phase Phospholipid

StaClot LA

Test Codes

Antrim #27073, EPIC: LAB5193, HEXPH

Instructions

Specimens with hematocrit values greater than 55% must have anticoagulant adjusted. Specimens must be re-collected using a specified whole blood to sodium citrate ratio. Contact the performing Laboratory for specific instructions.

Specimen Collection Criteria

Collect: One Light Blue-top 3.2% Sodium Citrate tube.

TUBE MUST BE FULL.

Physician Office/Draw Specimen Preparation

For optimal results, maintain whole blood specimen at room temperature (20-26°C or 68-78.8°F) prior to transport. Transport whole blood to the Laboratory within 4 hours of collection. If transport within 4 hours is not possible, the following procedure must be followed for accurate results:

  1. Centrifuge the capped tube at 1500 x g for 15 minutes.
  2. Transfer plasma with a plastic pipette into a plastic polypropylene centrifuge tube, cap and centrifuge an additional 15 minutes at 1500 x g to obtain platelet poor plasma (PPP) which has a platelet count less than 10 bil/L. Plasma with a platelet count of less than 10 bil/L is critical for accurate results.
  3. Immediately remove only the top two-thirds of the PPP and transfer it into a screw cap, 5 ml, 75 x 13 mm, round base, polypropylene tube. 
  4. Freeze (-20°C/-4°F or below) the PPP immediately.
  5. Transport frozen on DRY ICE. Specimen must remain frozen during transport.  

Preparation for Courier Transport

Transport: Whole blood at room temperature (20-26°C or 68-78.8°F), or plasma obtained through the process listed above, frozen (-20°C/-4°F or below).

Rejection Criteria

  • Glass tubes and 3.8% Sodium Citrate tubes.
  • Specimens that are clotted or grossly hemolyzed.
  • Inappropriate specimen volume.
  • Thawed or partially thawed specimens. 

In-Lab Processing

Whole blood specimens must be processed as follows upon receipt in the Laboratory:

  1. Centrifuge the capped tube at 1500 x g for 15 minutes.
  2. Transfer plasma with a plastic pipette into a plastic polypropylene centrifuge tube, cap and centrifuge an additional 15 minutes at 1500 x g to obtain platelet poor plasma (PPP) which has a platelet count less than 10 bil/L. Plasma with a platelet count of less than 10 bil/L is critical for accurate results.
  3. Immediately remove only the top two-thirds of the PPP and transfer it into a plastic tube.
  4. Test or freeze specimen according to lab protocol.

Storage

Specimen Stability for Testing:

Whole Blood
Room Temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Platelet Poor Plasma (PPP)
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Frozen (-20°C/-4°F or below): 30 days

Laboratory

Royal Oak Coagulation Laboratory

Performed

Results available in 1-7 days.

Reference Range

Normal Range: Negative screen or less than or equal to 7 seconds.
Equivocal: 8-12 seconds.
Positive: Greater than 12 seconds.

Test Methodology

Mechanical Clot detection (STart4).

Interpretation

Interferences:

  1. Heparin levels greater than 1 IU/mL may interfere in the test leading to falsely positive results.
  2. Thrombin inhibitors (e.g., hirudin, argatroban) may interfere in the test leading to falsely positive results.
  3. High C-Reactive Protein levels may interfere in the test leading to falsely positive results.
  4. Some specific inhibitors will interfere with this test.

The hexagonal phase phospholid test is designed for the qualitative detection of lupus anticoagulants. These LA immunoglobulins generally interfere with the phosopholipid-dependent tests such as the Activated Partial Thromboplastin Time (aPTT). Since other conditions such as antifactor antibodies, factor deficiencies and heparin can also cause the prolongation of the aPTT tests it is important to identify these LA antibodies. The comparison of the difference between the two clotting times of the plasma/buffer and the plasma/phospholipids is indicative of a positive or negative test. See reference range above.

Clinical Utility

This test can assist in the detection of a lupus anticoagulant.

CPT Codes

85597

Contacts

Last Updated

2/22/2021

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