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Test Code F9AS or LAB308 Factor IX Assay, Blood

Important Note

If the patient's hematocrit is > 55%, please call the lab to obtain a special blue top with an adjusted level of anticoagulant.

Specimen Requirements

Specimen Type:

Whole Blood

Container Type:

One Blue top: 2.7 mL or 1.8 mL

Optimal Collection Volume:
  • 2.7 mL in solid blue top tube or 1.8 mL in clear blue top tube.  The correct fill volume is indicated by the etched line on the tube.
  • Click here to view the specimen collection guide for blue top (citrate) tubes.

Collection Instructions:
  1. Do not draw from an arm with a heparin lock.
  2. If collected through a blood collection set (butterfly), a discard tube must first be drawn to eliminate dead space from tubing.
  3. Gently invert 5 to 10 times to mix blood.

Specimen Transport Temperature:
  • Room temperature. If testing is delayed, separate plasma and freeze (see outpatient collection instructions below).
  • Specimens cannot be refrigerated

Processing Instructions:
  1. Samples must be centrifuged within 4 hours of collection.
  2. If testing will be performed > 4 hours from collection time, samples should be processed to obtain platelet-poor plasma, aliquoted, and frozen.

Outpatient collections

  1. Spin down the sample, remove plasma, and spin plasma again to obtain platelet-poor plasma.
  2. Separate the platelet-poor plasma into a screw-top vial.
  3. Freeze plasma immediately.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Specimen Stability

Specimen Type

Temperature

Time

Whole blood

Room Temperature

4 hours

Platelet poor plasma

Room Temperature

4 hours

Platelet poor plasma

Frozen at -20 C

2 weeks

Specimen Rejection Criteria

  • Tube underfilled
  • Refrigerated specimen
  • Clotted specimen

Useful For

Decreased levels of Factor IX may be found in congenital deficiency or may be acquired secondary to other diseases such as liver disease, Disseminated Intravascular Coagluation (DIC) or due to a factor inhibitor.

Methodology

ACL TOP 500 - Factor IX activity in a patient’s plasma is determined by performing a modified activated partial thromboplastin time test (APTT). Patient plasma is diluted and added to a plasma deficient in factor IX. Correction of the clotting time of the deficient plasma is proportional to the concentration (% activity) of that factor in the patient plasma, interpolated from a calibration curve.

Reference Ranges

70-130%

Day(s) Performed

Routine testing

  • Monday through Sunday; performed on day shift

 

STAT testing

  • Available 24/7

Expected TAT

Same day to 3 days

Performing Laboratory

Bronson Laboratory, Coagulation - Kalamazoo

Sample Retention Time

24 hours

CPT Code

85250

LOINC Code

3209-4