The International Council for Standardization in Haematology (ICSH) is embarking on providing open-access guidance documents to enhance the quality of laboratory testing and practice. One recent ICSH initiative was to provide a guidance document for coagulation critical values, given that most critical value literature for coagulation testing only addresses basic screening tests (PT and APTT), fibrinogen and platelet count. This committee, comprised of renown experts in the coagulation field, developed this laboratory guidance document for 1) identifying all coagulation tests that have potential patient risk based on test, test result, and patient presentations, 2) recommending critical result thresholds; 3) providing acceptable reporting and documenting mechanisms, and 4) delineating the required elements for laboratory policies related to all phases of critical values or tests (testing, reporting and documentation).