Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques

Andrew J. Carter, Karen Hicks, Alan W. Heldman, Jon R. Resar, John R. Laird, Vicki J. Coombs, Jeffrey A. Brinker, Roger S. Blumenthal

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


A new microsample coagulation analyzer (Hemochron® Jr.) has recently been developed which performs a modified activated clotting time (ACT +) and an aPTT by using different reagents. The Hemochron® Jr. measures the clotting time of a 5-microliter whole-blood sample by an optical detector and extrapolates the results to the activated clotting time (ACT+) or the plasmaactivated partial thromboplastin time by using a validated regression analysis. We compared 124 simultaneous ACT+ and Hemochron® ACTs, and 53 paired Hemochron® Jr. aPTTs and hospital laboratory aPTTs, in 44 patients during coronary intervention. The Hemochron® Jr. aPTT closely correlated with the lab aPTT (r = .79, P < .0001), and the test results were available much more rapidly than the lab aPTT (3.5 ± 1.1 vs. 56.3 ± 25.5 min, P=0.0029). A comparison of duplicate ACT+ measurements did not identify a significant difference in the means (292 ± 115 sec vs. 293 ± 112 sec, P=0.72). The ACT+ closely correlated with the Hemochron® ACTs (r = .85, P < .0001). At baseline, the mean ACT+ (175 ± 43 sec) exceeded the Hemochron® ACT (144 ± 36 sec) by 22% (P < .001). After heparin administration, the mean ACT+ (378 ± 74 sec) exceeded the Hemochron® ACT (332 ± 65) by 12% (P < .001). The Hemochron® Jr. provides a fast and reproducible methodology for measuring ACT and aPTT, using a small blood volume. Further studies are required to determine the optimal anticoagulation range when using the Hemochron® Jr. during or after interventional procedures.

Original languageEnglish (US)
Pages (from-to)97-102
Number of pages6
JournalCatheterization and Cardiovascular Diagnosis
Issue number1
StatePublished - Sep 1996
Externally publishedYes


  • anticoagulation
  • heparin
  • PTCA

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


Dive into the research topics of 'Clinical evaluation of a microsample coagulation analyzer, and comparison with existing techniques'. Together they form a unique fingerprint.

Cite this