Optimizing an ethylenediaminetetraacetic acid decalcification protocol for diagnostic bone biopsies: experience at an...

Decalcification protocols are necessary for histologic assessment of bone biopsies. Strong acid-based decalcification is rapid but detrimental to nucleic acids, while ethylenediaminetetraacetic acid (EDTA) is less harmful but time-consuming. We aimed to standardize a decalcification protocol to optimize turn-around time and tissue preservation. Diagnostic bone core needle biopsies were radiographed for baseline mineralization, fixed in formalin, and transferred to EDTA. Interval radiography was performed until specimens were deemed sufficiently decalcified. Histotechnologists and pathologists evaluated overall histopathologic quality (great, good, poor). Final specimen radiographs were qualitatively assessed for mineralization density (black, gray, white) and distribution (absent, unifocal, multifocal). Logistic regression models were fit to compare the proportion of cores with adequate section quality by mineralization density and distribution, and to infer dose-response relationships, accounting for age, sex, and repeated measurements. Effect size and statistical significance were reported using odds ratios (OR) for non-poor histology and p-values. Fifty-two core needle bone biopsies were collected from 34 patients. Cases with absent mineralization (100%, 6/6) or unifocal gray mineralization (92%, 12/13) typically showed non-poor histology. Cases with multifocal white mineralization often (60%, 3/5) showed poor histology (absent versus multifocal: β = 18.42, p = 0.048; black versus white mineralization: β = 21.091, p = 0.043). Cases with multifocal gray mineralization showed variable results, with 68% (19/28) showing acceptable histology. Minimizing decalcification in select cases may decrease turn-around time without compromising diagnostic accuracy. Complete absence of calcium by specimen radiography is unnecessary to achieve high-quality histologic processing and microscopic analysis.