Immunohistochemistry and immunofluorescence utilization audit by subspecialty in an academic setting: A step toward stewardship.

There are immunohistochemistry (IHC) and immunofluorescence (IF) panels described in the literature and established by personal and institutional experiences that are in common use by pathologists in their daily practice. Stewardship is a difficult discussion because IHC utilization is influenced by many factors including the pathologist's experience, background, practice setting, personal bias, and medicolegal culture. We developed the methodology to audit the IHC/IF utilization in our academic subspecialty practice. We aim to share this methodology and to provide our data that can be used for consideration by other subspecialized academic practices. This analysis included a total of 63,157 specimens that were accessioned during 2022, representing 38,612 cases. The likelihood of ordering IHC/IF ranged from 1 % (in genitourinary pathology) to 59 % (in renal pathology). The average percentage of specimens with IHC/IF was 21 % for the entire practice. In cases where IHC/IF was ordered, the number of stained slides averaged 4.9 per specimen for the entire practice. The number of IHC/IF slides per specimen ranged from 1.9 (in gastrointestinal pathology) to 12.2 (in renal pathology). The highest number of antibodies ordered for a single specimen by subspecialty ranged from 11 (in cardiac pathology) to 63 (in dermatopathology). Renal pathology was the only subspecialty that had an average number of IHC/IF slides that was statistically significantly different from all other subspecialties. We described the various patterns of utilization by subspecialty and rationalized their subtle differences. We also analyzed the types of cases that exceeded the reimbursement limits set by the Centers for Medicare and Medicaid Services (CMS).

Reliability of histologic assessment for NAFLD and development of an expanded NAFLD activity score.

BACKGROUND AND AIMS: The NASH Clinical Research Network histologic scoring system, the gold-standard NASH histology assessment for clinical trials, has demonstrated intrarater and interrater variability. An expert panel in a previous systematic Research and Development/University of California Los Angeles (RAND/UCLA) study determined that existing histologic scoring systems do not fully capture NASH disease activity and fibrosis, and standardized definitions of histologic features are needed. We evaluated the reliability of existing and alternate histologic measures and their correlations with a disease activity visual analog scale to propose optimal components for an expanded NAFLD activity score (NAS). APPROACH AND RESULTS: Four liver pathologists who were involved in the prior RAND/UCLA study underwent standardized training and multiple discussions with the goal of improving agreement. They were blinded to clinical information and scored histologic measures twice, ≥2 weeks apart, for 40 liver biopsies representing the full spectrum of NAFLD. Index intraclass correlation coefficient (ICC) estimates demonstrated intrarater (0.80-0.85) and interrater (0.60-0.72) reliability. Hepatocyte ballooning items had similar interrater ICCs (0.68-0.79), including those extending scores from 0-2 to 0-4. Steatosis measures (interrater ICCs, 0.72-0.80) correlated poorly with disease activity. Correlations with disease activity were largest for hepatocyte ballooning and Mallory-Denk bodies (MDBs), with both used to develop the expanded NAS (intrarater ICC, 0.90; interrater ICC, 0.80). Fibrosis measures had ICCs of 0.70-0.87. CONCLUSIONS: After extensive preparation among a group of experienced pathologists, we demonstrated improved reliability of multiple existing histologic NAFLD indices and fibrosis staging systems. Hepatocyte ballooning and MDBs most strongly correlated with disease activity and were used for the expanded NAS. Further validation including evaluation of responsiveness is required.