Question: Our nurse administered Prevnar 13 to a patient who had already purchased the vaccine. We only billed 90471, but we were denied due to a lack of serum code. How should we bill this? Tennessee Subscriber Answer: In a situation where the patient provides their own vaccine, you may still need to provide a serum code — in this case 90670 (Pneumococcal conjugate vaccine, 13 valent (PCV13), for intramuscular use) for the Prevnar 13 — in addition to the administration code 90471 (Immunization administration (includes percutaneous, intradermal, subcutaneous, or intramuscular injections); 1 vaccine (single or combination vaccine/toxoid)). However, you will use a zero dollar or one penny charge for the vaccine. This is because many payers cannot determine coverage and payment for the vaccine administration unless they know what drug or vaccine your practice administered. Providing the code with a zero or nominal charge alongside is the best way to give them that information.