Factor IX

The liver produces a protein called factor IX (F-IX), vital in the natural coagulation process. A triggering agent (factor IX A) activates FI-X upon injury and damage to the blood vessels. The activated variant then enables blood vessels to clot, preventing excessive bleeding.

A factor IX deficiency usually leads to haemophilia B, a bleeding disorder in which blood fails to clot naturally. Some other symptoms of the condition include the following:

• Unusual nosebleeds
• Excessive bleeding from minor cuts or bleeding from a previous wound
• Oral bleeding
• Blood in stool or urine
• Bruises for no apparent reason

In terms of severity, haemophilia B can be life-threatening if not managed or treated consistently. Even a minor impact on the head could lead to internal bleeding in the brain, which can be fatal. In such cases, internal cerebral bleeding will manifest as the symptoms listed below:

• Sudden headache
• Pain or stiffness in the neck 
• Drowsiness 
• Impairment in motor functions

A factor IX deficiency often stems from associated genetic history and predominantly affects males. Females who inherit one defective Factor IX gene do not show visible symptoms and become carriers. There is a 50% chance of their male babies developing the condition in such cases.

There are some instances of acquired factor IX deficiency (stemming from external sources instead of genetics). Some factors that cause the same include the following:

• Vitamin K deficiency
• Liver diseases
• Anticoagulant medications such as clotting inhibitors or Warfarin therapy (rarely)

A factor IX test (F-IX test) is part of a more extensive screening test for bleeding disorders. In a clinical context, a deficiency in the protein leads to a diagnosis of haemophilia B. Test results also help assess the general levels of the protein present in an individual.

The F-IX test is performed in the Laboratory ACL TOP with the help of the activated partial thromboplastin time (APTT) method.

Testers combine the patient specimen with factor IX-deficient plasma. The compound then incubates for an allotted period alongside a reagent. Subsequently, calcium is added to the mix to activate the coagulation process.

Testers observe the clotting time through an optical device at a 671 nm wavelength. An assessment of the clotting time establishes F-IX concentrations in the patient specimen.

Infants under or equal to 6 months of age usually display decreased F-IX levels (20 unit/dL or less). The concentration levels increase as they age. In adults, normal levels range from 50-150 units/dL.

F-IX test results below 50 units/dL indicate haemophilia B, with severity levels increasing as the concentration drops. Conversely, elevated protein levels increase the chances of an individual developing deep vein thrombosis (blood clots in the veins).

Apollo 24|7 offers a factor IX test that assesses the associated protein levels to diagnose related disorders or deficiencies. The test result can also provide insight into the following:

• The impact of liver diseases on the production of F-IX and, thus, haemostasis (body’s natural response to stop bleeding)
• Additional implications behind a prolonged APTT (clotting time)
• Existence of other blood-related disorders such as thrombosis