The number of patients needing coagulation testing is growing, not only as part of the general trend toward higher test volumes, but because new applications for coagulation testing are being found. More patients are using anticoagulants for long periods (or permanently), particularly following implantation of mechanical heart valves or after episodes of atrial fibrillation.

An additional, more recently expanded group is using antithrombotic agents after, or to prevent, deep venous thrombosis, arterial or pulmonary embolism, stroke, angina pectoris, and myocardial infarction. Patients awaiting surgery, those with suspected disseminated intravascular coagulation, and those being screened for congenital clotting disorders also add to the list of candidates for coagulation tests.

In addition to mounting volumes, there is increasing pressure to return results to clinicians rapidly so that anticoagulant therapy can be fine-tuned, since outcomes appear to be tied to the successful use of anticoagulant therapy at a stable, effective level. As is so often the case, the laboratory is being expected to increase test volumes while decreasing turnaround times and costs. Manufacturers have adopted several strategies to help laboratories meet these goals, both in the clinical laboratory and at the point of care (POC).

SIEMENS HEALTHCARE DIAGNOSTICS BCS® XP

on the Market

SIEMENS HEALTHCARE DIAGNOSTICS, Deerfield, Ill, makes the BCS® XP system. This coagulation analyzer, introduced in 2006, is intended for high-volume work environments and has been optimized to improve turnaround time for results. Customer input, gathered during a series of interviews of many users of the other 1,500 installed systems in the BCS line, was used to add features that enhance workflow and improve productivity. For example, specialty and routine testing can be conducted simultaneously.

The system can use customer protocols to customize software that will enhance efficiency. In addition to employing state-of-the-art immunological, chromogenic, agglutination, and clotting methodologies on a single platform at three wavelengths, the system offers (for research use) advanced coagulation testing in the form of the automated endogenous thrombin potential test. For the detection of von Willebrand disease, there is an automated ristocetin cofactor activity test.

The system’s special features for handling high test volumes include the ability to manage both normal and pathological specimens using walk-away and random-access methods. The system’s specialty menu can be custom defined by the user to include profiles for disseminated intravascular coagulation and for the risk of thrombosis or bleeding, in addition to reflex testing.

Levels are monitored automatically for reagent bottles in tilted racks, and a dilution range of up to 1:1,200 is possible. Daily maintenance, the company says, uses a built-in quality-control (QC) package and requires less than 5 minutes of staff time.

ROCHE DIAGNOSTICS CoaguChek XS Plus

The CoaguChek XS Plus system from ROCHE DIAGNOSTICS DIVISION, Indianapolis, was introduced in 2007 as the company’s fifth-generation POC anticoagulation monitor, becoming part of the most frequently used family of prothrombin time (PT)/international normalized ratio (INR) POC testing devices in the United States. The CoaguChek XS Plus has FDA clearance for nonwaived services, and CLIA waiver approval is pending.

The device uses built-in QC, but external liquid controls also are available as an option. The battery-operated unit is handheld and is capable of storing 500 patient results or liquid QC results. PT/INR test results are searchable by date, testing time, and patient. Connectivity is provided for data management, and the meter has patient-identification, QC-lockout, and operator-lockout functions.

The system also can help providers comply with the 2008 patient-safety goals of The Joint Commission, which include coagulation-monitoring requirements intended to reduce adverse events and increase the amount of time that the patient spends in the therapeutic anticoagulation range. The system can be used to monitor clotting time in patients using warfarin, heparin, and low-molecular-weight heparin.

The single-chamber device uses the CoaguChek XS PT Test Strip and requires only a fingerstick blood sample. Results are available immediately, with two levels of onboard QC performed for each test to ensure reliability.

BECKMAN COULTER INC ACL® TOP

BECKMAN COULTER INC, Fullerton, Calif, offers the ACL* TOP family of systems (*ACL is a registered trademark of Instrumentation Laboratories). These hemostasis instruments are fully automated and are intended to make maximal use of available staff time in high-volume laboratories, with introduction of a model for medium-volume settings also planned. This user-friendly system family increases efficiency, the company says, in part because the system tells the operator what is needed to run a given test.

ACL TOP systems are capable of handling a full range of routine and specialty clotting, chromogenic, and immunoturbidimetric tests. LED technology is used to read most reactions at 671 nm, so results are unlikely to be affected by hemoglobin, bilirubin, or lipemia. These systems are designed for continuous operation, and no interruption is required to add stat samples (which can be placed in any position, in any rack, at any time).

In addition to the standard base system, the CTS closed-tube sampling system is available; it enhances safety and improves turnaround time by eliminating decapping/recapping steps. Samples, cuvettes, and reagents are loaded and unloaded continuously, and the system conducts hardware checks, monitors reagents, and tests samples simultaneously, around the clock. Abnormal results prompt automatic reruns and reflex testing; troubleshooting for abnormal samples is facilitated through the use of clot-signature curves. Reliability is ensured using an onboard QC program.

Hemosense INRatio®

The Hemosense INRatio® coagulation monitor is available from Inverness Medical Innovations Inc, San Diego. Among the most portable devices in its class, this POC system weighs only 300 g, even with its four AA batteries in place, and measures 16 x 7.5 x 5 cm. A single drop of capillary whole blood (obtained via fingerstick) is sufficient to conduct PT/INR testing.

QC functions are built into the device, with no need for external liquid QC, additional test strips, or another QC device for checking the electronic controls. The test strips used with the monitor require no refrigeration. The company states that materials costs are low for this device, that the test procedure calls for fewer steps than similar tests require, and that paperwork associated with coagulation testing is reduced through use of this device.

Users have an easy time of learning to operate this device because of its simple interface. In addition, the entire test procedure is streamlined: after insertion of a test strip into the monitor, a drop of blood is applied. Capillary action draws the blood into the test area to mix with reagents that start coagulation. After performing the PT test, the monitor conducts normal and therapeutic QC tests. Only if results for both QC tests are within preset limits will the device report the PT results.

Test results are available within 2 minutes and can be configured by the user to be displayed as PT; INR; PT with INR; or PT, INR, and QC. No matter which results are displayed, full results for 60 tests are stored in the unit, which has ports for electronic communications and printing.

DIAGNOSTICA STAGO STA-R Evolution

DIAGNOSTICA STAGO, Parsippany, NJ, manufactures the STA-R Evolution, which has a new design that includes a large, flat LCD touch screen and new Windows®-based software. Intended particularly to make it easy to complete the interface between laboratory automation systems and hemostasis testing, this instrument offers completely traceable samples and secured access to its operating menus.

A viscosity-based detection system is used to measure clotting, and optical density is used to measure chromogenic factors. The system’s onboard capacity is 220 samples, held in trays of 15 racks holding five samples each; 200 user-definable tests can be performed.

A bar-code reading system is incorporated, and dilutions and redilutions are performed automatically. There are 70 positions available for reagent vials of various sizes, including multiples of the same reagent. Tests available include PT, activated partial thromboplastin time (aPTT), fibrinogen, thrombin time, reptilase time, extrinsic and intrinsic pathway factors, heparin and low-molecular-weight heparin, antithrombin, protein C, lupus anticoagulants, protein S (total and free), von Willebrand factor, d-dimer, plasminogen, and antiplasmin, in addition to calibration and QC tests.

Tests can be added or run again at any time, with all tube sizes (including microtainers) being accepted. Stat condition can be assigned to any sample or to any entire rack. Clotting, chromogenic, and immunological assays can be run simultaneously. Automated cap piercing is available as an option.

The TEG® 5000 Thrombelastograph® hemostasis analyzer, offered by HAEMOSCOPE, a Haemonetics Corp company, Braintree, Mass, guides the user in determining effective treatment, in addition to finding the cause and extent of hemostasis problems. The system is particularly suitable for environments that have cost reduction as a priority, the company says, because it detects many clinical conditions rapidly and can be used as a POC test as well as in the laboratory. Its use can reduce the number of coagulation tests required to monitor the patient’s condition, in addition to decreasing the need for transfusion and repeated surgery.

Together, the TEG analyzer and its software indicate the balance (or lack of it) of the clot-forming and clot-dissolving mechanisms of the body. Data (such as tracings, numeric data, and normal values) can be viewed from any networked workstation or in the clinical unit nearest the patient. A graphical format for viewing clotting/lysis characteristics—in effect, a virtual clot—is also available, along with a Guide™ module that helps with differential diagnosis and results interpretation. The eConsult module can send tracings via e-mail for review anywhere, even using cellular telephones, and also can export numerical or graphical data to other information systems.

The TEG testing method is unique and has been in use worldwide, with continuous improvement, since its initial development in the 1940s. The analyzer uses an oscillating cup-and-pin arrangement to evaluate the properties of a clot as it forms from a whole-blood specimen. It identifies the time needed for initial formation of fibrin, the kinetics of the clot as it reaches maximal strength (shear elasticity), the stability of the clot (expressed as its ability to prevent hemorrhage without creating thrombosis), and its retraction or dissolution.

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The Cascade POC is made by HELENA LABORATORIES, Beaumont, Tex. This analyzer uses a reagent system that the company describes as uniquely useful for the monitoring of patients being treated with routinely used anticoagulant medications, in addition to those given antithrombotic agents. The device can be used with a conventional power supply or with a battery pack; its QC lockout capability makes it suitable for use in medical offices, anticoagulation clinics, emergency departments, operating rooms, and catheterization laboratories.

Additional assays are being developed for use with the device, but the tests currently being run on the Cascade POC are PT for whole or citrated blood, aPTT for whole or citrated blood, celite activated clotting time, and enoxaparin. The reaction chamber for each test is built into the test card, which uses bar coding to indicate, directly to the reader, the test’s calibration details, lot number, and type.

Electronic and biological QC are built in, along with automatic identification of the patient and the test operator. The device also incorporated an RS232 interface with the laboratory information system for data management.

Clearly, the manufacturers of coagulation analyzers are taking different approaches to improving the laboratory’s ability to perform coagulation tests quickly, reliably, and inexpensively. Some are concentrating on automation and high-volume systems, while others are focusing on simplicity and portability for POC testing. These are not actually opposite approaches, since both are intended to increase efficiency, and many facilities will benefit from using both. Meanwhile, manufacturers will continue to develop new instruments—along with new applications for older methods—to help their customers keep up with a demand that is unlikely to stop growing.

KRIS KYES IS TECHNICAL EDITOR OF CLP.