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Fibrinogen, Antigenic

Item Value
Approval req'd? No, however antigenic fibrinogen will only be performed if the functional fibrinogen is low.
Available Stat? No
Utilization Guidelines Should only be ordered in patients with low levels of fibrinogen by functional assay.
Test code FIBAG
Test group Fibrinogen
Performed by Quest
Sendout? Yes
Method Nephelometry
Patient Preparation Overnight fasting is required
Collection Instructions 1. Check the expiration date on the label of the blue top vacutainer before drawing the patient.

2. For blood collection in a sodium citrate blue top, the tube must be filled to above the Minimum Fill Indicator on the tube. It is crucial to wait and allow the tube to stop filling before removing it from the needle.

3. With use of a butterfly needle, draw about 1 cc using a separate blue top to remove air from tubing, discard the first tube and then draw a second blue top tube filled to the full extent of the vacuum.

4. Tubes should not be filled past the Maximum Fill dashed line by either using a syringe or removing the tube cap.
Container type Blue top filled to full extent of vacuum
Amount to Collect 2.7 mL blood
Sample type Citrated plasma
Preferred volume 1 mL plasma
Min. Volume 0.5 mL plasma (1.0 mL for LabCorp)
UCSF Rejection Criteria Samples collected in outdated blue top vacutainer. Over-filled or under-filled tubes may be rejected Hemolyzed sample.
Processing notes Central Processing: Deliver whole blood sample to Hematology Lab ASAP.

Hematology: Freeze plasma at -20C.

If approved, ship frozen to Quest Nichols, test code #37801X. For Brown & Toland patient, order BTMOLT. Ship frozen to LabCorp, test # 117052
Ref Lab Rejection Criteria Sample received unfrozen
Units mg/dL
Normal range 180-350 mg/dL
Synonyms Factor I; Fibrinogen antigen; Immunologic fibrinogen; Quantitative fibrinogen
Stability Refrigerated 3 days, frozen at -20C 3 months.
Turn around times Test is run Tuesday and Friday. Turnaround time: 7-10 days
Additional information Use only to evaluate suspected abnormal fibrinogen.

If an abnormal fibrinogen is suspected, a functional fibrinogen and immunologic fibrinogen (fibrinogen, antigenic) must be run on the same sample. Therefore, if only a fibrinogen antigen is ordered, a functional fibrinogen will be automatically added and separately charged. The Fibrinogen antigen will only be performed if the Functional Fibrinogen is low. If the Functional Fibrinogen is normal, then the Fibrinogen antigen will be cancelled with the notation: Test Not Indicated. In the rare circumstance in which the functional fibrinogen is normal and an assessment for dysfibrinogenemia is nevertheless essential, please contact the hematology laboratory (Parnassus: 3-1747, Mission Bay: call 6-0194) to request that the immunologic fibrinogen be performed.

Rare individuals have a bleeding diathesis or a thrombotic tendency due to the presence of an abnormal fibrinogen (dysfibrinogenemia). This is most commonly hereditary, but dysfibrinogenemia with a bleeding tendency can be acquired in liver disease. Performing functional fibrinogen and immunologic fibrinogen on a plasma sample permits diagnosis of dysfibrinogenemia. Thrombin time and reptilase time are not necessary for diagnosis of dysfibrinogenemia.
CPT coding 85385-90
LOINC code 42772-4
Last Updated 1/29/2015 4:25:23 PM
Entry Number 384
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