Page 712 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

696 PART 8 ■ Fundamentals of Hematological Analysis

COAGULATION PROCEDURES (continued)

Clinical Applications Second-generation TinaQuant (Roche), Liatest

Various types o anticoagulants may inter ere with coagula- latex agglutination (Stago), MDA D-dimer

tion at i erent stages, especially actor VIII, heparin-like (immunoturbidimetric) (bioMerieux)

activity, an antithromboplastins. Most acquire antico- Source: Adapted from Righini M, Perrier A, De Moerloose P, et al. D-Dimer

agulants are autoantibo ies (usually IgG, sometimes IgM) for venous thromboembolism diagnosis: 20 years later, J Thromb Haemost,

irecte against specif c coagulation actors. Below is a list o 6:1059–1071, 2008.

circulating anticoagulants associate with clinical isor ers.

Approximately 5% to 10% o patients with SLE, many patients

on phenothiazine therapy, patients taking a variety o me ica- T e classic microplate ELISA was consi ere the gol stan-

tions, an patients with lymphoproli erative isor ers may em- ar or measuring d- imer. o ay, more than 30 i erent

onstrate inhibitors known as lupus-like anticoagulants. d- imer assays are commercially available. T ese assays rep-

In a ition to testing or circulating anticoagulants to spe- resent a wi e range o techniques.

cif c coagulation actors, the platelet neutralization proce ure EUGLOBULIN LYSIS TIME

(PNP) an the tissue thromboplastin inhibition test ( I )

may be valuable. T e PNP test separates lupus-like inhibitors Principle

rom actor VIII, X, an V inhibitors but oes not istin- Te euglobulin raction o plasma contains plasminogen, f brin-

guish the presence o heparin rom an acquire inhibitor. T e ogen, an activators with the potential or trans orming plas-

I proce ure is less specif c than the PNP but screens or minogen to plasmin. T is raction is precipitate with 1% acetic

lupus-like anticoagulant with inhibitory activity against tis- aci an resuspen e in a borate solution. T e euglobulins are

sue thromboplastin. Details o the PNP an I proce ures then clotte by the a ition o thrombin. T e clot is incubate ,

can be oun in works o Lenahan an Smith. an the time o lysis is reporte . Clinically, the euglobulin lysis
test is a screening proce ure or f brinolytic activity.

T is proce ure, in CLSI ormat, is provi e on this book’s
BIBLIOGRAPHY companion Web site at http://thepoint.lww.com/ urgeon6e.

Provi e on this book’s companion Web site at http://thepoint. MIXING STUDIES AND FACTOR ASSAYS

lww.com/ urgeon6e.

Mixing Studies (Circulating Anticoagulant Screen,

D-DIMER ASSAY Screening for Circulating Inhibitor)

Principle Principle: P mixing stu y is in icate when the P is

Te un amental principle o the d- imer assay has remaine prolonge in the absence o heparin therapy. T e assay is

largely unchange : recognition o the unique neo-epitope in prece e by a thrombin time to etect therapeutic heparin

d- imer by specif c antisera. d- imer contains a neo-epit- or a irect thrombin inhibitor. A mixing stu y is per orme

ope that is orme ollowing the cross-linking o a jacent D by measuring the AP in the patient’s plasma, then mixing

omains by actor XIIIa. It is this epitope that is recognize an equal volume o the patient’s plasma an normal poole

by specif c antisera use in clinical assays. plasma (NPP) an repeating the AP tests imme iately an

a er 37°C incubation.
Commercially Available D-Dimer Assays I the results o the mixing stu y show correction or both

the imme iate an incubate P /aP tests, the patient
Method Vendor most likely has a coagulation actor ef ciency (or multiple

actor ef ciencies). I the results o the mixing stu y show
Microplate ELISA Asserachrom D-di (Stago),

Enzygnost (Dade-Behring) no correction in either the imme iate or incubate P /aP ,
the patient may have a coagulation inhibitor, such as lupus
ELISA and uorescence Vidas DD (bioMerieux), Stratus anticoagulant. I the mixture’s P result oes not correct,

(ELFA) D-dimer (Dade-Behring) the patient may have an inhibitor. T ere are specif c inhibi-

ELISA and Pathfast (Mitsubishi), Immulite tors such as anti– actor VIII, associate with blee ing, an

chemiluminescence (Siemens) lupus anticoagulants, associate with thrombosis. I the

Immuno ltration and NycoCard (Nycomed), Cardiac results o the mixing stu y show correction or the imme i-

sandwich-type D-dimer (Roche) ate P /aP results, but no correction in the incubate P /

aP , the patient may have a slow-acting inhibitor such as
Semiquantitative latex Dimertest latex (IL), Fibrinosticon

agglutination (bioMerieux) anti– actor VIII ( able 32.4).
Note: Correction o the AP in the mixing stu y suggests
Manual, whole-blood SimpliRED (Agen), Clearview a coagulation actor ef ciency in either the intrinsic path-

agglutination Simplify D-dimer (Agen) way ( actors VIII, IX, XI, an XII; high-molecular-weight