Lab Test

High Molecular Weight Kininogen

HMWK, Fitzgerald Factor

Test Codes

ARUP: 2007578, EPIC: LAB6271, Beaker: XHMWK

Department

Send Outs

Instructions

Do not draw from an arm with a heparin lock or heparinized catheter.

Specimen Collection Criteria

Collect: Two Light Blue-top Sodium Citrate tubes.

  • TUBES MUST BE FULL.
  • Transport specimen to the Laboratory immediately after collection for processing.

Physician Office/Draw Specimen Preparation

For optimal results, maintain whole blood Sodium Citrate specimens 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 transfer 2mL PPP into a plastic transport tube.
  4. Freeze (-20°C/-4°F or below) the PPP specimen immediately.
  5. Transport frozen on DRY ICE. Specimen must remain frozen during transport. 

Preparation for Courier Transport

Transport: Whole blood in Sodium Citrate 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

Specimens not collected or processed as indicated.

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 transfer 2mL PPP into a plastic transport tube.
  4. Freeze (-20°C/-4°F or below) the PPP specimen immediately.
  5. Transport frozen on DRY ICE. Specimen must remain frozen during transport. 

Transport: Whole blood in Sodium Citrate 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).

Storage

Specimen Stability for Testing:

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): 14 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to ARUP Laboratory in Salt Lake City, UT. Forwarded to LabCorp Esoterix, Calabassas Hill, CA.

Performed

Varied
Results available in 6-15 days. 

Reference Range

By report.

Test Methodology

Clot-based.

Interpretation

By report.

Clinical Utility

Aid in evaluating the cause of an isolated prolonged PTT in a patient who is not currently bleeding.

CPT Codes

85293
LOINC:  52754-9

Contacts

Last Updated

7/7/2021

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