Any hospital authority created by and under this chapter shall conduct an annual audit of the financial affairs, books and records of such authority, the audit to be at the end of each fiscal year. Each hospital authority shall obtain either a certified public accountant or a firm of certified public accountants to conduct such audit. The auditor so appointed shall make the audit provided for in this section in accordance with generally accepted accounting principles, and shall submit the complete and final report and audit to such authority not later than ninety (90) days after the close of the fiscal year. All audits provided for in this section shall be certified to and shall include, but in no way be limited to, a full and complete audit containing a balance sheet, profit and loss statement and statement of receipts and disbursements, and shall certify whether or not the authority has operated within its approved annual operating budget and capital budget.