Which of the following principles measures the actual coagulation ...

[Sufayan.ah]

Which of the following principles measures the actual coagulation protein rather than fibrin formation?
 
  a. Photo-optical
  b. Mechanical
  c. Chromogenic
  d. Immunologic

Question 2

Which of the following assays uses indirect measurement using a chromogenic substrate to quantitate heparin?
 
  a. Protein C
  b. Thrombin time (TT)
  c. Anti-Xa assay
  d. Fibrinogen assay

[joechoochoy]

Answer to Question 1

ANS: D
Immunologic methods measure the actual coagulation protein rather than fibrin formation. These assays are based on antigen-antibody reactions.

Answer to Question 2

ANS: C
The heparin anti-Xa assay is used to indirectly measure the concentration of heparin. In this system, heparin has an inhibitory effect on the enzyme Xa. Xa normally proteolytically cleaves the chromogenic substrate, releasing the chromogen with a color intensity that is then measured. Because heparin has inhibited some of the Xa, less free Xa will be available to cleave the substrate and less color will be released. Thus the concentration of heparin is inversely proportional to the activity of Xa. This is classified as an indirect measurement.

[Sufayan.ah]

Thanks for the timely response, appreciate it

[Zebsrer]

TYSM