Coding guides
Short, practical explainers on how the U.S. medical code sets work, written for billers, coders and anyone reading a claim.
The reliable workflow: alphabetic index first, tabular list second, and specificity checks before the code goes on a claim.
One reports why the patient was treated, the other reports what was done during an inpatient stay. They are not interchangeable.
Why a category code like E11 cannot be billed, what a header code is, and how 7th characters work.
The seven axes of a PCS code, decoded with a real example from the Medical and Surgical section.
CPT is Level I. Everything else - ambulance, DME, drugs, supplies - is Level II. Who maintains what, and why this site lists Level II only.
New, deleted and revised codes in the FY2027 ICD-10-CM and ICD-10-PCS files, and the three places stale codes hide in a practice.
A worked example: one hospital stay and one office visit, and which code set answers which question on each claim.