COMMUNITY ENDOCRINE SURGICAL EXPERIENCE WITH FALSE-NEGATIVE AFIRMA GEC® RESULTS: 2011-2017.

OBJECTIVE: Afirma Gene Expression Classifier® (Afirma GEC) molecular analysis (Veracyte, Inc, San Francisco, CA) is a negative predictive value test developed to reduce the number of thyroidectomies in thyroid nodule patients with indeterminate cytology. GEC technology has reportedly reduced unnecessary thyroid surgery, but few studies have examined Afirma GEC false-negative rates, since usually patients with GEC benign nodules do not undergo surgery for definitive diagnosis. Occasionally, Afirma GEC benign patients require removal of their thyroid nodules for other reasons; this work describes the incidence of malignancy and noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) in this population. METHODS: We reviewed our community endocrine surgical practice database for patients who had undergone thyroid surgery from January 2011 through April 2017 despite benign Afirma GEC results. RESULTS: Afirma GEC testing was completed for 475 patients during the study period. Surgery was clinically indicated for other reasons in 42 of the 193 patients (22%) with Afirma GEC benign results. Malignancy or NIFTP in the targeted nodule was found in the final histologic evaluation of 14 of the 42 Afirma GEC benign surgical patients. The Afirma GEC false-negative percentage for our incomplete surgical group (FNP-ISG), defined as the surgically proven false negatives divided by the total Afirma GEC benign patients, was 7.3%. CONCLUSION: Our high surgical rate in Afirma GEC benign nodules reveals an FNP-ISG of 7.3% in our community endocrine surgical patient population; this value exceeds the 5.7% reported in the multicenter 2012 Afirma GEC validation study. ABBREVIATIONS: Afirma GEC = Afirma Gene Expression Classifier; FNA = fine-needle aspiration; FNP = false-negative percentage; FNP-ISG = false-negative percentage for an incomplete surgical group; NIFTP = noninvasive follicular thyroid neoplasms with papillary-like nuclear features.

Quantifying the value of in-house consultation in surgical pathology.

In-house consultation is a well-known method to improve diagnostic accuracy and agreement, but the technique has not been well studied. We reviewed the results of in-house consultation in a large private hospital practice setting for a 1-month period and determined its effect on diagnostic accuracy using the final sign-out as the "gold standard." During this 1-month period, 352 cases were reviewed as in-house consultations. Initial complete agreement was found in 315 (89.5%) cases. Using the initial diagnosis as the test case and the final sign-out as the gold standard, of the 37 discrepant cases, 4 (1.1%) were thought to represent false-negative results, (0.3%) a false-positive result, 3 (0.9%) differences in type, and 29 (8.2%) differences in diagnostic threshold. Disagreements in 10 cases were thought to be potentially clinically significant. Internal consultation was obtained on approximately 20% of all cases seen in the laboratory and disagreements were found in 2% of all cases. Internal consultation has a significant and measurable impact on the practice of surgical pathology.

Blinded review as a method for quality improvement in surgical pathology.

CONTEXT: Several studies have shown that blinded review, because it is less biased and may improve vigilance, is an excellent method for detecting errors and improving performance in gynecologic cytology. The value of blinded review in surgical pathology is not known. OBJECTIVE: To determine the value of blinded review in surgical pathology. METHODS: Five hundred ninety-two biopsy cases were reviewed without knowledge of the original diagnosis or history, and the results were compared with those of the original diagnosis. RESULTS: Complete agreement was obtained in 567 (96%) of 592 cases. The technique of blinded review of biopsy material had a sensitivity of 98%, failing to identify a lesion in 7 cases; no cases of malignancy were missed. The specificity was 100%. Differences in diagnostic threshold were the most common source of disagreement. False-negative cases were identified by the technique and were clinically significant. Power studies show that the number of cases requiring review to identify significant errors are large, but potentially achievable by blinded review. CONCLUSION: Blinded review is a sensitive and effective method for identifying areas of disagreement, including false-negative cases, and for decreasing errors in surgical pathology biopsy material.