(A representative evidence table evaluating the anticoagulation studies is shown in Supplemental Table 1; study appraisals of randomized controlled trials and meta- analyses are shown in Supplemental Table 2; and the Newcastle-Ottawa appraisal for nonrandomized studies is depicted in Supplemental Table 3). Duties of the Writing Group Members of the writing group wrote and developed rec- ommendations based on review of the articles obtained us- ing the search technique described above. The quality of information for a given recommendation allowed assess- ment of the level of evidence as recommended by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines (avail- able at: http://www.americanheart.org/downloadable/ writing_committees.pdf). The Appendix contains a summary of recommendations put forth in this guideline as a result of the evidence base. Heparin Dosing for Initiation and Maintenance of CPB Class I Recommendation  A functional whole blood test of anticoagulation, in the form of a clotting time, should be measured and should demonstrate adequate anticoagulation before initiating and at regular intervals during CPB. (Level of Evidence C) Class IIa Recommendations  Bolus administration of unfractionated heparin based on weight is reasonable for achieving adequate anticoagulation, but individual response to heparin is heterogeneous and requires a therapeutic functional test of clot inhibition before initiation of CPB, independent of the bolus dose used. (Level of Evidence C)  It is reasonable to use activated clotting time (ACT) tests that produce maximally activated clotting times as these tests mitigate ACT variability, are less susceptible to hypothermia, and correlate more closely with factor Xa activity compared with tests that use a single activator. (Level of Evidence B)  It is reasonable to maintain activated clotting time above 480 seconds during CPB. 