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Test ID CH9 Chromogenic Factor IX Activity Assay, Plasma

Advisory Information

Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, ALBLD / Bleeding Diathesis Profile, Limited, Plasma is recommended.

Necessary Information

If a priority specimen, mark request form, give reason, and request a call-back.

Specimen Required

See Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.


Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Polypropylene vial

Specimen Volume: 1 mL

Collection Instructions:

1. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

2. Aliquot plasma a separate plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

3. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally at ≤-40° C.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.

Useful For

Monitoring coagulation factor replacement therapy of selected extended half-life coagulation factor replacements


Aiding in the diagnosis of hemophilia B using a 2-stage assay, especially when a 1-stage assay was normal

Testing Algorithm

This assay is indicated in situations where there is a clinical suspicion of hemophilia B diagnosis, when the 1-stage assay is normal. However, this assay is also recommended for accurate classification of hemophilia B.


See Hemophilia Testing Algorithm in Special Instructions

Reporting Name

Chromogenic FIX, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reference Values



Chromogenic Factor IX activity generally correlates with the one-stage FIX activity. In full term/premature neonates, infants, children, and adolescents the one-stage FIX activity* is similar to adults. However, no similar data for chromogenic FIX activity are available. (Appel JTH 2012; 10:2254)


*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.

Day(s) and Time(s) Performed

Monday through Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
CH9 Chromogenic FIX, P 88449-4


Result ID Test Result Name Result LOINC Value
CH9 Chromogenic FIX, P 88449-4

NY State Approved


Method Name