This page discusses the Clinical Laboratory Improvement Amendments (CLIA) that regulate clinical laboratories to assure test accuracy and reliability. Labs are classified by test complexity, influenci...This page discusses the Clinical Laboratory Improvement Amendments (CLIA) that regulate clinical laboratories to assure test accuracy and reliability. Labs are classified by test complexity, influencing certification and training. State agencies enforce compliance through inspections and proficiency testing, which is required for nonwaived tests. Labs must meet performance standards, or they risk corrective actions or loss of certification.