Coagulation Laboratory Testing Practices in a 2001 Survey of 800 Randomly Selected U.S.
Hospitals
S. Shahangian, A.K. Stankovic, I.M. Lubin, J.H. Handsfield, and M.D. White
Div Lab Systems, CDC, Atlanta, GA 30341-3717
Objective:
To assess variability of hospital coagulation laboratory practices.
Outcome:
Prevalence of selected laboratory practices.
Methods and Setting:
From a sampling frame of institutions listed in the 1999 directory of the
American Hospital Association, we randomly selected 800 hospital coagulation
laboratories (sampling rate, 14%). Six-hundred and thirty-two responded
(response rate, 79%). A group of coagulation experts and survey methodologists
assisted in the design of this 2001 survey, and they further evaluated the
content and format of the survey before pilot testing. We excluded inconsistent
responses from further analysis.
Results:
Ninety-seven percent stated they performed coagulation testing. Almost all
(99.8%) reported PT results as international normalized ratio (INR), 97%
reported results in seconds and/or as therapeutic PT ratio, and 3% reported
results as INR only. Seventy-five percent reported using 3.2% sodium citrate as
anticoagulant, and 27% reported using 3.8% sodium citrate. Seventeen percent
reported determining the sensitivity of PT assay to heparin, and 50% reported
selecting PT-thromboplastin reagents insensitive to heparin in the heparin
therapeutic range. Sixty-four percent reported they had an aPTT therapeutic
range for heparin when monitoring heparin therapy. Ninety-six percent assayed
specimens for aPTT within 4 hours after phlebotomy, and 88% centrifuged
specimens within 1 hour of collection. Fourteen percent reported monitoring low
molecular weight heparin (LMWH) therapy; 72% used aPTT assay to monitor LMWH
therapy while 53% used an anti-Xa assay to do so.
Generalizability:
Due to the high response and sampling rates, results of this survey appear
to be generalizable.
Conclusion:
We found substantial variability in certain coagulation laboratory
practices. Some of these practices are not consistent with current guidelines,
and they may affect patient outcome. This calls for concerted intervention
efforts.
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