Utilization Review; Objection to Utilization Review Determinations; Timeliness. Court of Appeal, denying defendant's petition for writ of error, held that parties, pursuant to Labor Code § 4062(a)'s "by mutual agreement" provision, correctly engaged in resolution of dispute stemming from utilization review determination that neurosurgical consult requested by agreed medical evaluator was not medically necessary, when Court of Appeal found that defendant, by questioning agreed medical evaluator on deposition long after expiration of 20-day period specified by Labor Code § 4062(a) for objecting to utilization review determinations, indicated its agreement to submit matter to WCAB; Court of Appeal held that defendant had waived defense of applicant's failure to timely object to utilization review determination, pursuant to Labor Code § 4062(a), by raising defense for first time in its petition for reconsideration. © Copyright 2010 LexisNexis. All rights reserved. See Trimas Corp. v. W.C.A.B. (Rendon).