Fibrinogen Antigen, Nephelometry

Cleveland Heartlab Coagulation/Platelet Function, F, Test


CPT Code: 85385
Order Code: C334
ABN Requirement:  No
Specimen: Sodium Citrate Plasma
Volume: 1.0 mL
Minimum Volume: 0.5 mL
Container: Sodium Citrate (Light Blue Top) Tube


  1. Collect and label sample according to standard protocols. It is important to fill the tube to the fill-line.
  2. Gently invert tube 3-4 times immediately after draw. Do not shake.
  3. Centrifuge for 15 minutes.
  4. Immediately aliquot sodium citrate plasma into transport tube labeled as “NaCit Plasma” and cap tightly. Discard original tube.

Fasting: Overnight fasting is required.

Transport: Store plasma refrigerated or frozen after collection and ship the same day of collection per packaging instructions included with the provided shipping box.

Note: If the specimen will be delayed longer than 48 hours, specimen must be shipped frozen. Centrifuge light blue top specimen for 15 minutes at 2500-3500 rpm. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet (buffy) layer and place into a plastic screw-cap vial transport tube and freeze at -20 degrees C. Ship on dry ice.


Ambient (15-25°C): Not Acceptable
Refrigerated (2-8°C): 3 days
Frozen (-20°C): 90 days

Causes for Rejection: Specimen received at room temperature; specimens collected in anticoagulants other than sodium citrate; improper labeling; samples not stored properly; samples older than stability limits; hemolysis; lipemia

Methodology: Nephelometry

Turn Around Time: 1 to 5 days

Reference Range:

Age mg/dL
All Ages 180-350

Risk Range:

Sex Low Risk


Moderate Risk


High Risk


Male and Female <350 N/A ≥350

Priority Value:

Age Priority 2 Value (mg/dL)
All Ages <100

Clinical Significance: Low levels of fibrinogen are associated with bleeding most commonly secondary to liver disease or Disseminated Intravascular Coagulation (DIC). Fibrinogen is an acute phase reactant and thus elevated levels may be associated with inflammation. Fibrinogen can also be elevated due to hypercoagulability, pregnancy, oral contraceptive use, smoking, and postmenopausal status. Increased concentrations are also associated with increased risk of atherosclerosis.

Limitations: Grossly lipemic samples and samples that have very high triglycerides should be avoided. Clotted samples should be avoided.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.