Hospitals do not price "a colonoscopy". They price code 45378, and separately 45380 and 45385, each of which is a colonoscopy. The description on the bill is the hospital's own wording; the code is the standard. If you want to compare prices, dispute a bill or read a price file, the codes are the language, and there are four families you will meet.
CPT codes: procedures and services
Current Procedural Terminology codes are five-digit numbers maintained by the American Medical Association. They describe what a clinician or facility did: office visits (99203 to 99215), imaging (70450 CT head, 72148 MRI lumbar spine), tests (80053 metabolic panel, 85025 blood count), procedures (45378 colonoscopy, 47562 gallbladder removal) and surgery. Nearly every outpatient service is billed with a CPT code, and the hospital's facility fee and the doctor's professional fee use the same code with different modifiers.
Modifiers are two characters added to a code: -26 means the professional (reading) part only, -TC the technical part only, -50 both sides, -59 a separate service. A price file row with a modifier is a different price from the bare code, which is why this site skips modified rows.
HCPCS codes: supplies, drugs and Medicare-specific services
The Healthcare Common Procedure Coding System has two levels. Level I is CPT. Level II codes are one letter followed by four digits, maintained by Medicare: J codes for injectable drugs (J1885 ketorolac), G codes for Medicare-defined services (G0121 screening colonoscopy), A codes for supplies, E codes for equipment. In hospital price files the column "code type" says CPT for some rows and HCPCS for others, and hospitals are inconsistent about which label they use for the five-digit codes; this site treats CPT and HCPCS five-digit numeric codes as the same thing.
MS-DRG codes: inpatient stays
Medicare Severity Diagnosis Related Groups are three-digit numbers that classify an entire inpatient stay by the principal diagnosis or procedure and by complications: 470 is a hip or knee replacement without major complications, 807 a vaginal delivery without complications, 392 a digestive disorder stay. A DRG price covers the hospital's charge for the whole admission (room, nursing, operating room, supplies), but not the physicians. Most insurers use DRGs or something similar for inpatient contracts, which is why the price files list them. There are about 770 of them.
Revenue codes: the department
Revenue codes are three- or four-digit codes on the hospital's claim that say which department generated a charge: 0250 pharmacy, 0300 laboratory, 0320 radiology, 0360 operating room, 0450 emergency room, 0110 to 0170 room and board by type. On an itemized bill, every line has one. In price files, revenue codes appear as an additional code on many rows, and some negotiated rates are defined by revenue code (for example, a percentage of charges for everything under 0250) rather than by CPT.
Chargemaster and local codes
Every hospital keeps a chargemaster: its internal list of every billable item with an internal number (CDM code) and a gross charge. Price files usually list the CDM code alongside the standard code. Two CDM lines can carry the same CPT code with different prices, which is how "HEAD CT" and "HEAD CT LIMITED" both end up as 70450. When this site shows "lowest of 3 lines", that is what it means.
Reading a price file row
A row in the CMS template says: description, one or more codes with their types, setting (inpatient or outpatient), gross charge, discounted cash price, then for each payer and plan the negotiated dollar amount (or a percentage or algorithm where the contract is not a fixed dollar figure), the methodology, and the de-identified minimum and maximum across all payers. Put together, one code at one hospital can be 50 rows in a tall file or 50 columns in a wide one.
Why the code matters more than the words
Two hospitals will describe the same service differently and the same hospital will describe two different services similarly. The code is the only thing that is the same everywhere, and it is what your insurer, the hospital's contract and the federal rule all use. When you ask for a price, ask by code. When you check a bill, check the codes. When a description does not match what happened, the code is your evidence.