<p>Laboratory diagnostic tests in rheumatology laboratories are subject to the regulations of the German Medical Association, whose guidelines on quality assurance for laboratory medical examinations (Rili-BÄK) are binding. Quality assurance covers the entire process—from sample collection, transport, and distribution to analysis and diagnosis. We present examples of typical procedures in the rheumatology laboratory and discuss key aspects of quality assurance. The laboratory diagnostic procedures used should comprise CE-marked in vitro diagnostic devices. The introduction of tests into the laboratory requires clinical evidence of the validity of the tests. In addition, the procedures must be verified/validated, performed under quality control, and evaluated in a&#xa0;meaningful way. Participation in laboratory comparisons ensures correct implementation. The article concludes with information on professional law and reimbursement issues.</p>