good clinical laboratory practice good clinical laboratory practice good clinical laboratory practice (gclp) is a gxp guideline for laboratory samples from clinical studies. good clinical practice (gcp) does not define requirements for laboratories and good laboratory practice (glp) focusses on pre-clinical analyses and not on human samples from clinical trials. the research quality association (rqa) suggested in 2003 a guideline to close the gap. later the world health organization and the british medicines and healthcare products regulatory agency issued their own versions of a gclp guideline. literature who good clinical laboratory practice (gclp) isbn 978-92-4-159785-2 stevens w. (2003) good clinical laboratory practice (gclp): the need for a hybrid of good laboratory practice and good clinical practice guidelines/standards for medical testing laboratories conducting clinical trials in developing countries. quality assurance, 10: 83–89. grant, vanessa and stiles, tim, research quality association (2003 and revised in 2012), good clinical laboratory practice isbn 978-1-904610-21-2