Background: The College of American Pathologists (CAP) launched the Pathology and Laboratory Quality Center in 2010 to develop and implement laboratory practice guidelines (LPGs). Twelve LPGs have been published. In 2013, CAP was awarded a 5-year cooperative agreement from the United States Centers for Disease Control and Prevention to increase the effectiveness of LPGs.

Objectives: To assess the awareness, adoption and impact of a CAP LPG published in 2014 in comparison to baseline data from 2010.

Methods: A baseline survey on immunohistochemical (IHC) assay-validation practices had been conducted in 2010. Subsequently, an LPG addressing the gaps in practice was published in 2014. In 2015, a follow-up study consisting of three different evaluation modalities (a questionnaire, telephone interviews and focus group sessions) was conducted on CAP and non-CAP laboratories to determine the impact of the LPG and inform future updates.

Results: A total of 1624 (out of 3512 distributed) questionnaires, 40 (out of 231 attempted) telephone interviews and 5 (out of 24 invited) focus group responses were analysed. All modalities indicated the majority of respondents were aware of the LPG and had adopted most or all of recommendations. The questionnaire demonstrated that a significantly higher percentage of laboratories had written procedures for IHC validation (p