What does high collagen ADP mean?

The collagen/ADP test is run to confirm an abnormal collagen/adrenaline test. If both tests are abnormal, the patient may have a platelet function disorder and further testing for inherited or acquired bleeding disorders is indicated.

What is PFA collagen ADP?

Test Information. The PFA is a screening test for platelet dysfunction. The cartridge membrane is coated with collagen, and with one of two platelet agonists (epinephrine or ADP). The platelets adhere to the collagen and aggregate in response to the collagen and epinephrine (or ADP).

What is normal PFA?

Normal closure times range from 77 to 133 seconds for the Col/ADP membrane and 98-185 seconds for the Col/Epi membrane. The PFA-100 has been tested in persons with bleeding disorders.

What is ADP in hematology?

Adenosine diphosphate (ADP) is a platelet agonist that causes platelet shape change and aggregation as well as generation of thromboxane A2, another platelet agonist, through its effects on P2Y1, P2Y12, and P2X1 receptors.

What is a PFA blood test for?

The PFA is a screening test for platelet dysfunction. The cartridge membrane is coated with collagen, and with one of two platelet agonists (epinephrine or ADP). The platelets adhere to the collagen and aggregate in response to the collagen and epinephrine (or ADP).

Why does ADP activate platelets?

ADP is actively secreted from platelet dense granules but is also passively released from damaged erythrocytes and endothelial cells. Most platelet agonists, including ADP, activate platelets via cell surface receptors coupled to heterotrimeric GTP-binding proteins or G proteins.

How does ADP activate platelets?

ADP not only causes primary aggregation of platelets but is also responsible for the secondary aggregation induced by ADP and other agonists. ADP also induces platelet shape change, secretion from storage granules, influx and intracellular mobilization of Ca2+, and inhibition of stimulated adenylyl cyclase activity.

What happens if collagen / ADP test is normal?

If both tests are abnormal, the patient may have a platelet function disorder and further testing for inherited or acquired bleeding disorders is indicated. If the collagen/ADP test is normal, then the abnormal collagen/adrenaline test may be due to aspirin ingestion.

How are platelets coated with ADP and collagen?

Platelet Function Assay (PFA) ADP/Collagen. The PFA is a screening test for platelet dysfunction. The cartridge membrane is coated with collagen, and with one of two platelet agonists (epinephrine or ADP). The platelets adhere to the collagen and aggregate in response to the collagen and epinephrine (or ADP).

What is the PFA ADP / collagen assay?

Platelet Function Assay (PFA) ADP/Collagen. The cartridge membrane is coated with collagen, and with one of two platelet agonists (epinephrine or ADP). The platelets adhere to the collagen and aggregate in response to the collagen and epinephrine (or ADP). The response measured is known as the Closure Time (CT) and is reported in seconds.

Which is more sensitive to hemostasis, Col or ADP?

The COL/EPI membrane is more sensitive to disorders of primary hemostasis, but is less specific. A prolonged closure time with COL/EPI membrane and a normal closure time with COL/ADP may be the result of: