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HelpTest Code LAB3030 Chromogenic Factor X
Clinical System Name
Factor 10 Assay, Chromogenic
Description
Coagulation Factor X (Stuart Power Factor, FX) is a vitamin K dependent protein produced by the liver. It has a central position in the coagulation cascade. Factor X is activated by both the extrinsic and intrinsic systems before exerting its effect on the conversion of prothrombin to thrombin. Patients who need anticoagulation therapy can be treated with warfarin, which is a vitamin K antagonist. This treatment leads to a decrease in all vitamin K dependent clotting factors and thus a prolonged clotting time. The therapy requires careful monitoring since it is essential to find the optimal balance between risk of thombosis and risk of bleeding for each patient. The measurement of Factor X is a useful tool in the management of patients with lupus inhibitors receiving warfarin thereapy, or patients on direct thrombin inhibitors (DTIs).
Sample Requirements
Specimen: Whole Blood
Container(s): Lt Blue/Citrate
Required Vol: (1) 1.8 mL or (1) 2.7 mL
Minimum Vol: N
Note: This is enough for a PT, PTT, TT, Fibrinogen and Chromogenic FX to be run on the same sample.
Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume. Use of a Vascular Access Device for the collection of coag testing is not recommended. Please review the Coagulation Lab Collection Job Aid for detailed instructions.
Processing Instructions: Main Campus
Deliver whole blood to Coag bench. Coag Technologist will process.
Reject due to: clotted, insufficient quantity (underfill), or improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: Core 14 Freezer ( -70 C).
Specimen should be centrifuged within one hour of collection. Transfer upper 3/4 layer of plasma to plastic tube affixed with large Epic aliquot label. Do not pool. Assay immediately.
Processing Instructions: Offsite & Regional Clinics
Reject due to: clotted, insufficient quantity (underfill), or improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: -70 C (preferred) or -20 C.
Specimen should be centrifuged within one hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large sample label. Freeze one aliquot of plasma at -70 C (preferred) or -20 C. Preferred plasma volume: 1.0 mL, minimum plasma volume: 0.6 mL. Do not pool.
Non-Children's Hospital Offsite collection: Ship completely frozen on dry ice.
Children's Hospital Regional Clinic collection: Ship completely frozen in frozen Nalgene Labtop cooler with ice pack inside an insulated soft cooler.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Citrated platelet-poor plasma | Room temp | ≤4 h |
| Refrigerated | N | |
| Frozen -20 C or -70 C | ≤3 m |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Coagulation
Phone Number: 206 987-2617 (Client Services)
Synonyms
LAB3030
Chrom FX
Chromogenic Factor 10
Chromogenic Factor X
Availability
| STAT | Performed | TAT |
|---|---|---|
| Y |
Daily |
1 h |
Methodology
Method: Chromogenic substrate assay by STA-R MAX
Analytical Volume: 100 uL plasma
Limitations: Method is affected by moderate lipemia, moderate hemolysis, moderate icterus, insufficient quantity (underfill), improper collection (overfill), improper processing, and improper storage. High hematocrit greater than or equal to 56% requires a citrate adjusted tube.
Reference Range
50 - 150%
CPT Codes
85260
Critical Values
None