VIII WF = von Willebrand factor
(VIII C does not function in the absence of other parts).
¾ In hemophilia A the VIII C portion is defective so there
is lack of clotting activity but platelet function is normal.
¾ In von Willebrand’s disease VIII R: AG is missing so there
is abnormal platelet function alongwith lack of clotting
activity (VIII C portion does not function alone).
Laboratory Diagnosis of Hemophilia
¾ Activated partial thromboplastin time raised.
¾ Whole blood coagulation time prolonged in severe cases.
¾ Factor VIII clotting assay (VIII C) lowered.
¾ Immunological methods show normal VIII R: AG.
¾ Bleeding time and prothrombin time tests are normal
¾ Carrier females have half the clotting activity (VIII-C)
expected for the level of VIII R: AG.
Christmas Disease (Hemophilia B)
¾ Activated partial thromboplastin time prolonged
¾ Whole blood clotting time raised (in severe cases)
¾ Factor IX clotting assay diminished
¾ Both bleeding time and prothrombin time tests are
¾ Low levels of factor VIII clotting activity (VIII C)
¾ Low levels of factor VIII related protein VIII R:AG
¾ Defective platelet aggregation with ristocetin. The
aggregation response to other agents (collagen,
thrombin, adrenaline) is normal.
¾ In some patients there is defective retention of platelets
Hemorrhagic Disease of Newborn
¾ The prothrombin time and activated partial thromboplastin time are both prolonged
¾ The platelet counts and fibrinogen levels are normal
with absent fibrin degradation products.
AUTOMATION IN COAGULATION ANALYSIS
has ten inbuilt incubation positions for sample and one
location for reagents (Fig. 10.1).
¾ It allows the user to make all basic tests for the analysis
of plasmatic hemostatic phase, e.g. Quick test (PT),
aPTT, TT, fibrinogen, defective factors, etc.
¾ It is a totally open instrument to be used with all kinds
of quality reagents, simply by following the producers
¾ Optical group: Made up of a Wolfram lamp at low
voltage and long self-life, an optical light pass, the
reaction cell holder and a solid state photocell which
registers all absorption changes produced.
¾ Thermostatic block: Thermostated device at 37 + 0.1°C
with magnetic stirrer motor built-in.
¾ Screen: Four digit indicator with tenth of second
precision, thermostatic block control temperature LED
(37°C) and two operation keys, the chronometer can be
used seperately to control incubation time.
¾ Tests: Quick Test (PT), aPTT, TT, Fibrinogen, deficiency
¾ Power requirements: AC 220 V. 50 Hz 120 VA
¾ Dimensions: 180 × 300 × 140 nm
System Automatic single channel coagulometer based
on turbo-photometric clot detection system
Measurement Opto-mechanical measuring system
Automatic start of measurement on addition of
reagent/sample for precise result
On screen digital chronometer to measure
Sensitivity Highly-sensitive in all measuring range because of Opto-mechanical measuring system
(combination of optical controls with mechanical movement of magnetic stirrers)
Incubator Inbuilt Incubator (solid state) fixed at 37°C
Incubator lodges 10 reaction cuvettes and
Testing mode PT, APTT, TT, fibrinogen and factor assays
Lamp source Low voltage tungsten lamp
Motor For stirring action of magnetic stirrer
Display Back illuminated LCD with single row and
Power supply 220V, 50 Hz/60 Hz
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