Which code set for which type of data?

The correct answer: C. A clinical drug described by ingredient, strength, and dose form: RxNorm

✅ Why this answer

RxNorm is a standard naming system for clinical drugs, published by the National Library of Medicine (NLM). It describes a drug by its active ingredient, strength and dose form, and links different brand and generic names to a single concept, so prescribing and pharmacy systems understand each other.

❌ Why the other options are wrong

• (A): lab tests such as potassium are coded with LOINC, not RxNorm.
• (B): a physician visit as a professional service for billing is coded with CPT. LOINC is for lab tests and clinical observations.
• (D): supplies and equipment such as a wheelchair are coded for billing with HCPCS Level II. SNOMED CT is for clinical concepts in documentation.

💡 Key concept

A quick table to remember:

• ICD-10 (International Classification of Diseases, 10th revision): diagnoses (and inpatient hospital procedures in the US version, ICD-10-PCS).
• CPT (Current Procedural Terminology): physicians’ professional services and procedures.
• HCPCS (Healthcare Common Procedure Coding System) Level II: supplies, equipment and services such as ambulance transport.
• LOINC (Logical Observation Identifiers Names and Codes): lab tests and clinical observations.
• RxNorm: clinical drugs.
• SNOMED CT (Systematized Nomenclature of Medicine Clinical Terms): detailed clinical concepts in documentation.

In the exam: the shortest path is to name the kind of data first (a test, a drug, a diagnosis, a service, a supply), then choose the standard made for it. The wrong options pair a real standard with a kind of data it does not cover.

🔗 Related facts and questions

• The two levels of HCPCS: Level I is CPT itself, issued by the American Medical Association (AMA). Level II is issued by CMS (the Centers for Medicare & Medicaid Services) for supplies, durable medical equipment (DME), ambulance services and some drugs given in the clinic, such as the J codes for injected drugs.
  Practice question: a physician gives a patient an injection in the clinic. The claim has two lines: one for the service of giving the injection, and one for the drug itself. Which code set is used for each line? → The service with CPT, and the drug with HCPCS Level II (a J code).
• ICD-10-CM versus ICD-10-PCS: CM (Clinical Modification) is for diagnoses in every care setting. PCS (Procedure Coding System) is for inpatient procedures on the hospital’s claim only. Outpatient procedures and physicians’ services are coded with CPT.
  Practice question: an inpatient had surgery. Which code set does the hospital use for the procedure on its claim, and which does the surgeon use on the professional claim? → The hospital uses ICD-10-PCS, and the surgeon uses CPT.
• RxNorm versus NDC: the NDC (National Drug Code) identifies a specific package from a specific manufacturer. RxNorm groups the different packages and brand names under one clinical concept, such as “amoxicillin 500 mg capsule”, and links it to all the matching NDC codes.
  Practice question: a pharmacy inventory system must tell apart two boxes of “amoxicillin 500 mg capsule” from two different manufacturers. Which code does it use? → NDC, because RxNorm groups them under one concept.
• How LOINC builds a code: each test has a code that combines six axes, including what is measured, the kind of specimen and the method. So potassium in blood has one code, and potassium in urine has another.
• Terminology versus classification: SNOMED CT is a very detailed clinical terminology whose concepts are linked to each other, suited to documentation and decision support. ICD is a classification that groups conditions into categories for statistics and billing. Maps exist from SNOMED CT to ICD-10-CM, so documentation uses the first and billing the second.
• Who issues each code set: ICD-10-CM: the National Center for Health Statistics (NCHS). ICD-10-PCS and HCPCS Level II: CMS. CPT: the American Medical Association. LOINC: the Regenstrief Institute. RxNorm: the National Library of Medicine (NLM). SNOMED CT: SNOMED International.
• ICD-10 for coding the diagnosis for billing: a related question in the full bank.
• SNOMED CT for precise clinical documentation: a related question in the full bank.
• Vocabularies specific to some specialties: "Otolaryngology (ENT) and specialty vocabulary" (in the full bank).
• The electronic prescription and its messaging standard: "The NCPDP SCRIPT standard for electronic prescriptions" (in the full bank).