Interobserver agreement and risk of malignancy using the International Academy of Cytology Yokohama System for reporting breast FNA biopsy in a liquid-based exclusive cohort.

BACKGROUND: Per the College of American Pathologist's National Breast Fine Needle Aspiration Biopsy (FNAB) Practice Survey, ∼40% of laboratories use liquid-based cytology (LBC) for breast FNAB. The reproducibility of the International Academy of Cytology Yokohama System (YS) for reporting breast FNAB on LBC was explored. DESIGN: Breast FNAB specimens submitted as LBC only (all ThinPrep) between January 2017 and January 2021 were retrieved. Cases without histopathologic follow-up were excluded. Clinical and radiologic information was collected. One cytologist and six cytopathologists rendered diagnoses per YS. All reviewers were blinded to the original diagnosis and histopathologic follow-up. The risk of malignancy was calculated. Concordance rates were calculated by a weighted Cohen Kappa score (κ). RESULTS: Review of 110 cases demonstrated substantial to near-perfect agreement between each reviewer (κ = 0.73-0.91) and follow-up histopathology (κ = 0.66-0.85). The agreement was lowest in the inadequate (κ = 0.05) and atypical (κ = 0.04) categories. The lack of concordance in the atypical category was common in cases with low cellularity or incomplete structural features. The risk of malignancy for inadequate, benign, atypical, suspicious for malignancy, and malignant categories were 12.5% (2/16), 3% (2/65), 67%, (8/12) 100% (1/1), and 100% (16/16). CONCLUSION: Interobserver agreement is excellent using the five YS categories in LBC. Lack of cellularity and incomplete architectural features were barriers to perfect agreement. Established pitfalls in the interpretation of LBC were cause for atypical diagnoses. Continuous training and education are recommended to avoid misdiagnosis because of the nonconventional cytomorphologic features of LBC and to improve inadequate and atypical rates within YS.

Do Serum Creatinine Levels Show Clinically Significant Fluctuations on Serial Determinations on the Siemens Advia 1800 Analyzer?

BACKGROUND: The goal of this work was to determine whether there are clinically significant fluctuations in the level of serum creatinine on serial determinations, especially in the borderline range (1.1-1.3 mg/dl), after specimen storage. METHODS: Sixty-one serum samples were analyzed. They were divided into three categories based on the initial serum creatinine measurement: low (≤1.0 mg/dl), borderline (1.1-1.3 mg/dl), and high (≥1.4 mg/dl). The specimens were stored at 4°C and run on the Siemens Advia 1800 chemistry analyzer on days 1, 3, and 11. RESULTS: Statistical comparisons of the three groups were made using the unpaired t-test, yielding a two-tailed P-value for each group comparison. The P-values ranged from 0.0829 to 0.3892, indicating no statistically significant difference between the standard deviations of each group. CONCLUSIONS: Mild-to-moderate fluctuations in precision occur in successive serum creatinine determinations. The overwhelming majority of these fluctuations should not affect clinical decision making.