<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Austin, Melissa</style></author><author><style face="normal" font="default" size="100%">Ferrell, Chris</style></author><author><style face="normal" font="default" size="100%">Reyes, Morayma</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Do Elevated Hematocrits Prolong the PT/aPTT?</style></title><secondary-title><style face="normal" font="default" size="100%">American Society for Clinical Laboratory Science</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013-04-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">89-94</style></pages><doi><style  face="normal" font="default" size="100%">10.29074/ascls.26.2.89</style></doi><volume><style face="normal" font="default" size="100%">26</style></volume><issue><style face="normal" font="default" size="100%">2</style></issue><abstract><style  face="normal" font="default" size="100%">The Clinical and Laboratory Standards Institute guidelines require special processing of whole blood specimens with hematocrits greater than 55% due to the possibility of spurious prolongation of routine coagulation studies (PT, aPTT). As samples with hematocrits above 60% are rare at our institution, our study seeks to determine the effect of relative citrate excess on routine coagulation studies in samples with hematocrits of 60% to determine whether special processing is necessary. A calculated volume of 3.2% citrate was added to 1 mL aliquots of 40 whole blood samples in citrated tubes from adult patients to simulate a hematocrit of 60%. A dilutional control was created by adding an equivalent volume of saline to a separate 1 mL aliquot. Routine coagulation studies (PT, aPTT) were run on both samples on the STA Compact Analyzer in accordance with manufacturer instructions. While a paired Student's t-test demonstrated a clinically significant change in both PT and aPTT with the addition of citrate (p = 0.0002 for PT and p = 0.0234 for aPTT), clinical management would not have been altered by any observed change. More interestingly, we observed a shortening of 27/40 PTs and 23/40 aPTTs rather than the expected prolongation. Based on our data, no adjustment of citrate volume appears to be necessary in samples with hematocrits less than or equal to 60%.ABBREVIATIONS: CLSI - Clinical and Laboratory Standards Institute, PT - prothrombin time, aPTT - activated partial thromboplastin time, CBC - Complete Blood Count</style></abstract></record></records></xml>