This document, which is intended to serve as a guide for workforce preparation program providers, details the Illinois Occupational Skill Standards for clinical laboratory occupations programs. The document begins with a brief overview of the Illinois perspective on occupational skill standards and credentialing, the process used to develop the skill standards, and assumptions underlying the standards. Presented next are skill standards for each of 107 tasks typically performed by individuals employed in clinical laboratories. Each skill standard statement contains the following components: (1) a job summary; (2) the actual skill standard (including the conditions of performance, work to be performed, and performance criteria); (3) performance elements and assessment criteria; and (4) a recommended assessment and credentialing approach. The standards are grouped into the following categories: general laboratory skills; test management; body fluids; hematology; coagulation/hemostasis; microbiology; immunology; immunohematology and transfusion medicine; and chemistry. Appended are the following: glossary; lists of Illinois Occupational Skill Standards and Credentialing Council, Health and Social Services Subcouncil, and Clinical Laboratory Science/Biotechnology Cluster Standards Development Committee members; Health and Social Services Subcouncil Clinical Laboratory Science/Biotechnology Cluster Recognition Proposal; and list of workplace skills. (MN)