sc.judiciary.gov.ph/jurisprudence/2012/december2012/180440.pdf
"x x x.
The aforesaid medical reports/evaluations/certifications of different
doctors in favor of petitioner cannot be given probative value and their
contents cannot be deemed to constitute proof of the facts stated therein. It must be stressed that a document or writing which is admitted not as
independent evidence but merely as part of the testimony of a witness does
not constitute proof of the facts related therein.95 In the same vein, the medical certificate which was identified and interpreted in court by another
doctor was not accorded probative value because the doctor who prepared it was not presented for its identification. Similarly, in this case, since the
doctors who examined petitioner were not presented to testify on their
findings, the medical certificates issued on their behalf and identified by
another doctor cannot be admitted as evidence. Since a medical certificate
involves an opinion of one who must first be established as an expert
witness, it cannot be given weight or credit unless the doctor who issued it is presented in court to show his qualifications.96 Thus, an unverified and unidentified private document cannot be accorded probative value. It is precluded because the party against whom it is presented is deprived of the right and opportunity to cross-examine the person to whom the statements or writings are attributed. Its executor or author should be presented as a witness to provide the other party to the litigation the opportunity to question its contents. Being mere hearsay evidence, failure to present the author of the letter renders its contents suspect and of no probative value.97
x x x."
