Comparison of the i-STAT handheld activated clotting time with the Hemochron activated clotting time during and after percutaneous coronary intervention

Schussler, Jeffrey M.; Aguanno, James J.; Glover, Elizabeth N.; Vish, Nancy; Wissinger, Laurie A.; Schumacher, John R.; Wheelan, Kevin

doi:10.1016/s0002-9149(02)03249-6

Cited by 15 publications

(10 citation statements)

References 2 publications

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“…Overall, the i-STAT tends to yield lower values than the Medtronic, which might be explained by the fact that the i-STAT method is not based on the detection of a stable thrombus. 7 The Pearson correlation was R = 0.94 (P < .0001), indicating a statistically significant correlation between the 2 methods. The mean Medtronic value was 320 seconds (95% confidence interval, 284-356 seconds) compared with the mean i-STAT value of 312 seconds (95% confidence interval, 270-355 seconds), but this difference was not significant (2-tailed P = .31).…”

Section: Resultsmentioning

confidence: 88%

“…7 The correlation between the 2 methods was statistically significant, and the difference in values between the Medtronic and i-STAT was not significant.…”

Section: Discussionmentioning

confidence: 84%

“…The i-STAT ACT test has a number of advantages compared with ACT tests based on mechanical clot detection as described by Schussler et al 7 First, the i-STAT is much less affected by temperature, dilution, and fibrinogen levels and is less dependent on user technique (although, in some circumstances, insensitivity to fibrinogen could also be a disadvantage). In addition, in our experience, when duplicate Medtronic values were compared with each other, the duplicates failed to agree within a limit of 12% about 13% to 15% of the time, necessitating rejection of the Medtronic test results.…”

Section: Discussionmentioning

confidence: 99%

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Clinical Evaluation of the i-STAT Kaolin Activated Clotting Time (ACT) Test in Different Clinical Settings in a Large Academic Urban Medical Center

Lewandrowski

Cott

Gregory

et al. 2011

American Journal of Clinical Pathology

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Historically, it has been difficult for hospitals to change methods for activated clotting time (ACT) testing because of differences in ACT values obtained with different instruments, wide differences in target ranges used in different procedures, and the difficulty of performing crossover studies at the bedside in critical care situations. There are limited published data comparing the i-STAT (Abbott Point of Care, Princeton, NJ) kaolin ACT with the Medtronic ACT Plus (Medtronic, Minneapolis, MN). The i-STAT system can perform ACT testing in addition to testing of a number of critical care analytes and may offer potential advantages over other ACT analyzers. Comparison of ACT values on 121 simultaneous split-sample tests yielded an R(2) of 0.88 with i-STAT = 0.79 Medtronic + 72.0. The Pearson correlation was R = 0.94, indicating statistically significant correlation between the 2 methods. Based on this comparison, we were able to implement the i-STAT ACT throughout our institution without changing target ranges for any individual procedure.

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Section: Resultsmentioning

confidence: 88%

“…7 The correlation between the 2 methods was statistically significant, and the difference in values between the Medtronic and i-STAT was not significant.…”

Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

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Clinical Evaluation of the i-STAT Kaolin Activated Clotting Time (ACT) Test in Different Clinical Settings in a Large Academic Urban Medical Center

Lewandrowski

Cott

Gregory

et al. 2011

American Journal of Clinical Pathology

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“…11 The correlation between the 2 devices was 0.526 in this study. 16 In another study, Actalyke ACTs were 18% lower than Hemochron ACTs, such that if the Hemochron target ACT of .480 seconds (for bypass) were applied to the Actalyke device, 50% of patients would receive increased heparin dosing to achieve the ACT goal. In heparinized specimens, 68% of the difference between i-STAT and Medtronics measurements could be attributed to the observation that the Medtronics device was affected by hemoglobin concentration, whereas the i-STAT was not.…”

Section: Comparison Of Different Act Devicesmentioning

confidence: 99%

Activated Clotting Time

Kratz

Cott

2005

Point of Care: The Journal of Near-Patient Testing &Amp; Technology

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T his report provides an overview and update regarding the advantages, disadvantages, and clinical uses of the activated clotting time (ACT) and a description of the devices that are commercially available to perform the assay. A discussion of recent peer-reviewed literature is then presented, focusing on articles published after 2001.The ACT is a whole-blood clotting time. 1 To perform this test, clotting is initiated in a blood sample by an activator of the intrinsic pathway of coagulation. The assay is most useful for monitoring high-dose heparin anticoagulation, in particular during cardiopulmonary bypass surgery. The activated partial thromboplastin time (PTT), another test that is normally used to monitor heparin, cannot be used to monitor such high heparin levels because the PTT is unclottable at high concentrations of heparin. Although the ACT is virtually always performed at the patient's bedside, the PTT is usually performed in a laboratory. Consequently, the turnaround time is usually much shorter for the ACT than for the PTT. Therefore, the ACT can also be used when an immediate measure of heparin anticoagulation is required at the bedside, such as with extracorporeal membrane oxygenation (ECMO), hemodialysis, cardiac catheterization, and vascular surgery. Only in rare circumstances are samples for the ACT collected in anticoagulated tubes with subsequent performance of the test in a central laboratory. 2 Analyzers from different manufacturers use different methodologies, and the results from different instruments are not interchangeable. Therefore, reference ranges vary considerably between instruments; they usually are between 70 and 180 seconds. The target ACT also depends on the ACT device/method used. With the high doses of heparin used during cardiopulmonary bypass, an ACT goal of over 400-500 seconds (commonly .480 seconds) is often used, representing a mean heparin level of approximately 4-5 U/mL. 2,3 For other indications, the ACT goal is typically lower.There are several limitations associated with the ACT. The ACT is less precise than the PTT, and the assay does not correlate well with the PTT or with heparin concentration (antifactor Xa levels). 2,4-6 Results are influenced by a variety of variables, including platelet count, platelet function, factor deficiencies, ambient temperature, hypothermia, hemodilution, and lupus anticoagulants. If a lupus anticoagulant is present, a heparin assay (anti-factor Xa levels) can be used to determine the level of anticoagulation. Aprotinin, an agent that is often used during cardiopulmonary bypass to decrease bleeding, can affect the results of some ACT methods. Aprotinin prolongs celite-based ACTs but generally not kaolin-based ACTs. Thus, celite-based ACTs may overestimate the amount of heparin anticoagulation when aprotinin is present. Very high doses of aprotinin, such as following a large initial bolus, may also prolong kaolin-based ACTs.

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“…Variations in response to heparin therapy can be related to its pharmacology, the patient, methods for monitoring therapeutic effect, or some combination of the above factors (4). ACT measurements can vary depending on the type of POC test system used, including different manufacturers (or the same); the source of formula of the activator; the amount of activator relative to sample volume; or the method of clot detection (3,(5)(6)(7)(8)(9)(10)(11)(12). Consideration of different POC test systems is emphasized in American College of Cardiology/ American Heart Association Percutaneous Coronary Intervention guideline, which recommends use of different target ACT values on the basis of the device type (13).…”

mentioning

confidence: 99%

Comparison of Point-of-Care Activated Clotting Time Methods in Different Clinical Settings in a Large Academic Medical Center

Korpi-Steiner

Walz

Schanzer

et al. 2017

The Journal of Applied Laboratory Medicine

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Objectives: This study is a comparative analysis of measured activated clotting time (ACT) values by use of 5 different point-of-care (POC) ACT methods spanning the range detected during different clinical procedures at our institution. Methods:We determined the correlation, imprecision, and differences in measured ACT values with use of 4 POC ACT methods compared with a reference ACT method in 41 venous whole blood samples collected from 25 adult patients undergoing interventional procedures. The POC ACT methods evaluated included the i-STAT with kaolin activator in prewarm mode, i-STAT with Celite activator in prewarm and nonprewarm modes, ACTPlus, and HMSPlus, which was designated the reference method. Each venous whole blood patient sample was tested in duplicate on each POC ACT test system (total n = 410 ACT measurements). Analyses of imprecision and differences in measured ACT values were stratified by moderate (100 -299 s) and high (≥300 s) ACT ranges. Results:In this study population, measured ACT values ranged from 100 -835 s with use of the HMSPlus. All methods demonstrated good correlation (r ≥ 0.95) in ACT values compared to the reference method. Imprecision varied by method with ranges of 1.7%-2.7% CV in the moderate ACT range and 2.5%-4.8% CV in the high ACT range. ACTPlus and i-STAT-Celite-prewarm methods exhibited proportional differences in measured ACT values whereas the i-STAT-Celite-nonprewarm and i-STAT-kaolin-prewarm demonstrated constant differences in measured ACT values compared to HMSPlus. Conclusions:ACT values correlate well between POC methods. Imprecision and difference profiles vary by method; notably, imprecision exceeds systematic differences in the high ACT range and contributes to intermethod differences that are limitations worthy of consideration when contemplating a change in ACT methods. IMPACT STATEMENTMeasurement of ACT is particularly useful during interventional clinical procedures involving use of heparin therapy to facilitate rapid decision-making for management of patient hemostasis. The present study findings demonstrate differences in measured ACT values between 5 different POC ACT methods and the effect analytical variables have on ACT test performance. Education of health-care professionals is needed regarding differences in measured ACT values if changing or interchanging ACT test systems.

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Comparison of the i-STAT handheld activated clotting time with the Hemochron activated clotting time during and after percutaneous coronary intervention

Cited by 15 publications

References 2 publications

Clinical Evaluation of the i-STAT Kaolin Activated Clotting Time (ACT) Test in Different Clinical Settings in a Large Academic Urban Medical Center

Clinical Evaluation of the i-STAT Kaolin Activated Clotting Time (ACT) Test in Different Clinical Settings in a Large Academic Urban Medical Center

Activated Clotting Time

Comparison of Point-of-Care Activated Clotting Time Methods in Different Clinical Settings in a Large Academic Medical Center

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