A licensed physician or pharmacist may receive controlled substances from or on behalf of a patient for qualitative or quantitative analysis purposes only, without an official order form, if within twenty-four hours of its receipt the physician or pharmacist mails or delivers the entire sample to a laboratory operated by the Commonwealth and designated by the Board to receive such substances. If the sample is mailed, it shall be sent by registered or certified mail, postage prepaid, with return receipt requested. If personally delivered, a receipt shall be obtained from such laboratory. All receipts or returns shall be kept on file for three years and shall be available for inspection by the Board at any reasonable time.