77 Pa. Stat. § 835
If any party or witness resides outside of the Commonwealth, or through illness or other cause is unable to testify before the board or a workers' compensation judge, his or her testimony or deposition may be taken, within or without this Commonwealth, in such manner and in such form as the department may, by special order or general rule, prescribe. The records kept by a hospital of the medical or surgical treatment given to an employe in such hospital shall be admissible as evidence of the medical and surgical matters stated therein.
Where any claim for compensation at issue before a workers' compensation judge involves fifty-two weeks or less of disability, either the employe or the employer may submit a certificate by any health care provider as to the history, examination, treatment, diagnosis, cause of the condition and extent of disability, if any, and sworn reports by other witnesses as to any other facts and such statements shall be admissible as evidence of medical and surgical or other matters therein stated and findings of fact may be based upon such certificates or such reports. Where any claim for compensation at issue before a workers' compensation judge exceeds fifty-two weeks of disability, a medical report shall be admissible as evidence unless the party that the report is offered against objects to its admission.
Where an employer shall have furnished surgical and medical services or hospitalization in accordance with the provisions of section 306(f.1), or where the employe has himself procured them, the employer or employe shall, upon request, in any pending proceeding, be furnished with, or have made available, a true and complete record of the medical and surgical services and hospital treatment, including X rays, laboratory tests, and all other medical and surgical data in the possession or under the control of the party requested to furnish or make available such data.
77 P.S. § 835