Anesthesia Coding Alert

Question: We’ve been having trouble with claims including 99100. What is the correct way to bill for it?

Kansas Subscriber

Answer: Code +99100 (Anesthesia for patient of extreme age, younger than 1 year and older than 70 [List separately in addition to code for primary anesthesia procedure]) is an add-on code you should only report when the patient meets the age criteria. The code indicates that the anesthesiologist’s work might be more involved because of the patient’s age.

Some coders append modifier 59 (Distinct procedural service) to the applicable anesthesia code before including +99100, but this is incorrect. It is a 1-unit code, so the fee will be whatever you bill per unit.

Note: Medicare does not pay additional units for +99100, but some other payers will. If your payer denies the claim with +99100, be prepared to appeal with documentation.