What are the other Names for this
Test? (Equivalent Terms)
- Factor VII (Proconvertin) Coagulation Blood
Test
What is Proconvertin Blood Test? (Background Information)
- The Proconvertin Blood Test is performed to
determine if an individual has deficient or decreased levels of Factor VII
- Clotting factors are proteins that help
form blood clots at the site of blood vessel injury. Blood clots stop blood
loss and allow the blood vessel to continue functioning
- The clotting of blood may be affected due
to the absence of clotting Factor VII, decreased levels of Factor VII, or
abnormal function of Factor VII
- Injury to a blood vessel causes the blood
vessel to constrict. Called the vascular phase, this is the first reaction of a
blood vessel to damage. It reduces the flow of blood to the site of injury,
minimizing blood loss
- Next, circulating platelets clump along the
site of blood vessel injury. Platelets form a foundation for a blood clot and
release chemicals that stimulate clotting
- The coagulation phase then causes a blood
clot to form. Clotting occurs when an enzyme called thrombin converts a soluble
protein, fibrinogen, into its insoluble form, fibrin. Fibrin proteins make up
the bulk of a blood clot
- Thrombin is activated by the merging of two pathways, called the intrinsic and extrinsic pathways, into the common pathway. These are initiated by different parts of the body after blood vessel damage:
- The intrinsic pathway begins in the blood with the activation of circulating proteins
- The extrinsic pathway begins in the blood vessel with the release of protein factors by damaged cells lining the vessel
- The extrinsic pathway is the first to
activate. The intrinsic pathway then reinforces the extrinsic pathway and
provides longer-lasting clotting effects
- Coagulation factors are central to the
action of these pathways. Each factor activates the next in a stepwise fashion
- Once a coagulation factor is activated, it
remains active. Thus, with each step in the pathway, more and more factors are
activated. This results in a cascade of events similar to the snowball effect
- A counter pathway ensures that the size of
the growing blood clot stays in check. Problems with this regulatory pathway
may lead to a dangerous condition where a blood clot forms within blood vessels
(thrombosis)
- The Coagulation Factors Blood Tests are
tests to help assess the activity and levels of 9 coagulation factors (though
there are 12 total). These tests are used to investigate bleeding disorders, especially
those that are genetic disorders
What are the Clinical Indications
for performing the Proconvertin Blood Test?
Following are the clinical indications for
performing the Proconvertin Blood Test:
- Following up to a prothrombin time (PT) or
partial thromboplastin time (PTT) blood test
- Bleeding related signs and symptoms:
Frequent bleeding from the nose, blood in stool and urine, easy bruising, and frequent
bleeding from the gums
- Before undergoing an elective surgery, if
there is a history of bleeding tendency; or, if there is uncontrolled or
excessive bleeding after a surgery
- Family history of coagulation Factor VII
deficiency
How is the Specimen Collected for Proconvertin Blood Test?
Following is the specimen collection
process for Proconvertin Blood Test:
Sample required: Blood
Process of obtaining blood sample in
adults:
- A band is wrapped around the arm, 3-4
inches above the collection site (superficial vein that lies within the elbow
pit)
- The site is cleaned with 70% alcohol in an
outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in
line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is
penetrated using the needle
- The required amount of blood sample is
collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed
on the collection site, and the needle is removed
- The blood is immediately transferred into
the blood container, which has the appropriate preservative/clot
activator/anti-coagulant
- The syringe and the needle are disposed into
the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special
preparation is needed prior to the test.
What is the Significance of the Proconvertin Blood Test Result?
Low levels of coagulation Factor VII may
indicate:
- A congenital deficiency of Factor VII
- Decreased production in the body of Factor VII,
due to a variety of reasons
- Liver disease
- Disseminated intravascular coagulation
(DIC)
- Vitamin K deficiency in the body
- Use of medication to prevent clotting
(anticoagulant medication)
- Malabsorption of fat
The laboratory test results are NOT to be
interpreted as results of a "stand-alone" test. The test results have
to be interpreted after correlating with suitable clinical findings and
additional supplemental tests/information. Your healthcare providers will
explain the meaning of your tests results, based on the overall clinical
scenario.
Additional and Relevant Useful
Information:
- Coagulation factors were named in the order
of their discovery. For example, Factor I was the first factor discovered.
Their names have nothing to do with the order in which they act during the
clotting process
- Factor VI was later proven to be a modified
version of Factor V. Thus, the name Factor VI is no longer used
Certain medications that you may be currently
taking may influence the outcome of the test. Hence, it is important to inform
your healthcare provider, the complete list of medications (including any
herbal supplements) you are currently taking. This will help the healthcare
provider interpret your test results more accurately and avoid unnecessary
chances of a misdiagnosis.
Please visit our Laboratory Procedures Center for more physician-approved health information:
http://www.dovemed.com/common-procedures/procedures-laboratory/
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