Cal. Civ. Proc. Code § 2032.610

(a) If a party submits to, or produces another for, a physical or mental examination in compliance with a demand under Article 2 (commencing with Section 2032.210), an order of court under Article 3 (commencing with Section 2032.310), or an agreement under Section 2016.030, that party has the option of making a written demand that the party at whose instance the examination was made deliver both of the following to the demanding party:
1. (1) A copy of a detailed written report setting out the history, examinations, findings, including the results of all tests made, diagnoses, prognoses, and conclusions of the examiner.
2. (2) A copy of reports of all earlier examinations of the same condition of the examinee made by that or any other examiner.
(b) If the option under subdivision (a) is exercised, a copy of the requested reports shall be delivered within 30 days after service of the demand, or within 15 days of trial, whichever is earlier.
(c) In the circumstances described in subdivision (a), the protection for work product under Chapter 4 (commencing with Section 2018.010) is waived, both for the examiner’s writings and reports and to the taking of the examiner’s testimony.