ITC Hemochron Signature+ Whole Blood Microcoagulation System - Manual (Page 2)

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INTENDED USE
The HEMOCHRON Jr. Signature+ Whole Blood Microcoagulation System is a battery-operated, hand-held
instrument that performs individual point-of-care coagulation tests on fresh or citrated whole blood. These
tests include: Activated Clotting Time (ACT+ and ACT-LR), Activated Partial Thromboplastin Time (APTT
and APTT Citrate), and Prothrombin Time (PT and PT Citrate). The system is intended to be used with test
cuvettes that are available from ITC.
Data management capabilities are included with the instrument. These capabilities include storage of up to
400 patient results and 400 quality control results, designation of quality control levels, tagging of test
results with date and time, entry of Patient ID and/or Operator ID, and printing of results.
HEMOCHRON Configuration Manager software is included. This software allows the user to connect a
personal computer to an instrument and perform system configuration functions using the fast and
convenient Microsoft
® Windows ® user interface. ITC data management software programs, provided
separately, allow the user to connect a personal computer to an instrument and perform various data
management and data reporting functions. Refer to the operating instructions for these programs for
information on use in conjunction with the HEMOCHRON Jr. Signature+.
For in vitro Diagnostic Use.
SUMMARY AND EXPLANATION
Events that lead to formation of a blood clot are simplified in coagulation theory into two interactive
coagulation cascades that are referred to as the intrinsic and the extrinsic pathways.
The clotting factors involved in these pathways are numbered I through V and VII through XIII. The intrinsic
pathway begins with the contact activation of factor XII and, through the interaction of several coagulation
factors, results in the conversion of soluble fibrinogen to insoluble fibrin strands. The extrinsic pathway is
initiated through the interaction of tissue factor with factor VII. Platelets, essential co-factors in this
reaction, provide the platelet phospholipid (PF3) surface on which coagulation reactions occur.
Heparin is used to maintain hemostasis during cardiac surgery and percutaneous coronary interventional
(PCI) procedures. However, its administration can pose significant risk to the patient since individual
patients can vary as much as twelve-fold in heparin sensitivity. Overdosing heparin can result in dangerous
bleeding, and underdosing heparin can lead to thrombosis. Therefore, monitoring heparin therapy is vital
in guarding against these undesirable side effects.
Activated Clotting Time (ACT+ and ACT-LR), Activated Partial Thromboplastin Time (APTT and APTT
Citrate), and Prothrombin Time (PT and PT Citrate) tests are general coagulation screening tests that are
used to measure the functionality of the blood coagulation cascade. The ACT test is the method of choice for
monitoring heparin therapy during cardiac surgery and PCI. Fresh whole blood is added to an activator
(Celite®, silica, kaolin, or glass particles), and then timed for the formation of a clot. The type of activator
used will affect the degree of prolongation of the ACT to a given heparin dose.
The HEMOCHRON Jr. ACT+ test uses a mixture of silica, kaolin, and phospholipids as an activator to create
a rapid and highly sensitive alternative to existing ACT tests. This test demonstrates linearity at heparin
concentrations ranging from 1.0 to 6.0 units of heparin per mL of blood, and it is not affected by high dose
aprotinin therapy.
The HEMOCHRON Jr. ACT-LR test uses a Celite activator due to its excellent heparin sensitivity. The test
demonstrates linearity at heparin concentrations up to 2.5 units of heparin per mL of blood. The test is not
intended for use with aprotinin therapy.
The HEMOCHRON Jr. APTT test measures the intrinsic coagulation pathway and involves all coagulation
factors except factors VII and III (tissue factor). The APTT test improves the PTT test through use of a
contact activating substance, which standardizes activation of Factor XII to provide a more precise and
sensitive assay for low level heparin monitoring. The HEMOCHRON Jr. APTT test is formulated to provide
optimal heparin sensitivity at heparin concentrations up to 1.5 units of heparin per mL of blood.
The HEMOCHRON Jr. APTT Citrate test performs the same measurement as the APTT test, using a citrated
whole blood sample.