Keep these guides in mind to help prove your case. Follow our real-world tips for choosing the best diagnosis to establish the need for anesthesia and help keep your reimbursement intact. Study the Patient's Circumstances Medicare defines "medical necessity" as services or items reasonable or necessary to diagnose or treat an illness or injury, or to improve the functioning of a malformed body member. Payers consider each case individually to determine if the treatment method is reasonable and necessary. Circumstances that help establish medical necessity for anesthesia can include: Medical conditions such as cancer, epilepsy, or seizure disorders. A danger of airway compromise because of sleep apnea. A history of being combative or the onset of diminished ability to comprehend what's happening. The need to establish and maintain the surgical field, such as coronary catheterization when the patient needs to be lightly sedated because of his participation during the procedure. The patient's age.For example: A physician is performing a magnetic resonance imaging (MRI) test on a child. Because the patient must sit still in order to complete the scan, anesthesia is necessary. In addition, this kind of example applies to adult patients who are mentally handicapped, psychotic, or unable to sit still because of pain or a physical condition. Without anesthesia, they would not be able to complete the exam or procedure. V code help: Old and new: Caution: Match the Diagnosis and Procedure Some payers have lists of approved diagnoses for procedures -- and those lists can be rather extensive. Submitting a diagnosis for a procedure that isn't on the payer's list can send your claim straight to denial. For example, diagnoses that can support medical necessity for monitored anesthesia care (MAC) during endoscopy can include: 250.00-250.03 -- Diabetes mellitus without mention of complication 278.01 -- Morbid obesity 401.9 -- Essential hypertension; unspecified 997.00 -- Nervous system complications, unspecified. Check your physician's documentation for any medical conditions or reasons supporting the need for anesthesia. If more than one diagnosis code applies, include all on your claim instead of singling out one. Dennis advises also including the reason for surgery on your claim, but check with your payer before taking that step. "If you need additional codes to explain the patient's physical status or the use of anesthesia, they're usually secondary," Dennis says. "However, I have seen a few carriers who specify that the additional codes to explain use of anesthesia may be reported as primary diagnoses over the reason for surgery." Pitfall: Only use the diagnosis codes that match your physician's documentation. If you choose codes just to get paid, you're setting yourself up for compliance issues. Check ICD-9's Symbols The colorful dots, triangles, and other symbols in ICD-9 aren't just there to look pretty -- they instruct you how to report certain diagnoses correctly. Pay special attention to the symbol or mark that defines "not first-listed diagnosis." You'll find this designation on codes such as 357.2 (Polyneuropathy in diabetes). "Give the symptoms or a more precise diagnosis," advises Jann Lienhard, CPC, a coder in New Jersey. For example, you might include a diagnosis such as 250.6x (Diabetes with neurological manifestations) in conjunction with 357.2. Warning: Watch for: