Question

4. What are four test systems that employ low reagent phospholipid concentrations to detect LA as a result of it prolonging the clot formation time? 5. Which two of these tests are used in combination by most specialty or reference laboratories in the United States to detect or help rule out LAs? 6. Why do LAs prolong phospholipid-dependent clot formation? 7. What is the effect upon clotting time of adding excess phospholipids and repeating a true- positive LA screening test? 8. How are mixing studies used to help confirm the presence of Las?! nomor 9. What is the definition of “hemophilia"?

Answer 1

Lupus anticoagulant was named so because it was first found in patients with SLE and prolonged partial thromboplastin time

4.Tests systems employing low reagent phospolipid concentration to detect LA:

a Tissue thromboplastin inhibition test.

b. Dilute Russell viper venom time (dRVVT).

c kaolin clotting time test.

d platlet nutrilization test.

e beta 2 glycoprotein 1 antibody test.

5 Test used in combination to detect or help rule out are:

LA sensitive PTT and dRVVT.

These are most sensitive tests used in combination.

6.Lupus anticoagulant will binds to phospholipids causes aPTT to prolong.

Name is misnomer as although it increases aptt but function as procoagulant and causes thrombosis.

Thrombosis can be due to it involves IgG antibody binding to phospolipids that are essential for normal activating and degrading effects of protein c and s.

7.On adding excess phospolipid, clotting time decreases..

8.Mixing studies are used to determine presence of Inhibitors.

Mixing positive titre: It indicate higher LA titre. They have higher risk of thrombosis.

Mixing negative titre: it indicatr lower LA titre. They have lower risk of thrombosis.

9.Hemophilia: It is inherited bleeding disorder due to deficiencies of fctor 8 or 9 where blood does not clot properly.

It leads to spontaneous bleeding or bleeding after injuries/surgeries.