Test Catalog

Test ID: FIBNG    
Congenital Fibrinogen Disorders, FGA, FGB, and FGG Genes, Next-Generation Sequencing, Varies

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

The laboratory workup for a congenital fibrinogen disorder begins with global coagulation screening assays.


In afibrinogenemia, prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin clotting time (TT) may be infinitely prolonged in afibrinogenemia.


In hypofibrinogenemia, TT is more sensitive than PT or aPTT for both quantitative and qualitative defects in fibrinogen.(1) Reptilase time (RT) maybe performed in addition to or instead of TT in samples known or suspected to contain heparin, which artificially prolongs TT.


PT, aPTT, and TT have poor sensitivity for mild fibrinogen deficiency or dysfunction. Further screening and identification of a mild fibrinogen deficiency or dysfibrinogenemia requires a clottable fibrinogen assay (typically Clauss-method based, eg, FIBTP / Fibrinogen, Plasma) to further test fibrinogen function as well as an immunologic (antigentic) assay (FIBAG / Fibrinogen Antigen, Plasma) to detect the quantity of fibrinogen present. Hypofibrinogenemia is indicated by a proportional decrease of functional and immunoreactive fibrinogen. Dysfibrinogenemia is indicated by a discrepancy between functional and immunoreactive fibrinogen.


Genetic testing for a congenital disorder of fibrinogen is indicated if:

-Coagulation tests indicate a quantitative or functional defect in fibrinogen

-Acquired causes of fibrinogen deficiency or dysfunction have been excluded (eg, thrombin clotting time [TT] may be prolonged by the presence of heparin, prior exposure to bovine thrombin, and high concentrations of serum proteins, as in multiple myeloma)

Specimen Type Describes the specimen type validated for testing


Advisory Information

Genetic testing for a congenital disorder of fibrinogen should only be considered if coagulation screening tests measuring thrombin clotting time (TT) with or without reptilase time (RT), clottable fibrinogen, and fibrinogen antigen labs are documented and indicate a quantitative or functional defect in fibrinogen, especially if these findings are similar between family members.

Shipping Instructions

Ambient and refrigerated specimens must arrive within 7 days (168 hours of draw), and frozen specimens must arrive within 14 days (336 hours of draw).

Collect and package specimens as close to shipping time as possible.

Necessary Information

Rare Coagulation Disorder Patient Information is required, see Special Instructions. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.

Specimen Required Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Submit only 1 of the following specimens:


Specimen Type: Peripheral blood


Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD) or green top (sodium citrate)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability: Ambient (preferred)/Refrigerated/Frozen


Specimen Type: Extracted DNA

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA and source of specimen.

2. Provide indication of volume and concentration of the DNA.

Specimen Stability: Frozen (preferred)/Refrigerated/Ambient

Special Instructions Library of PDFs including pertinent information and forms related to the test


1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.

Specimen Minimum Volume Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

Blood: 1 mL
Extracted DNA: 100 mcL at 50 ng/mcL concentration

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen TypeTemperatureTimeSpecial Container
VariesAmbient (preferred)7 days
 Frozen 14 days
 Refrigerated 7 days