Medical Coding Interview Questions 2026: Top 40 With Answers

Why These Questions Are Asked

Medical coding interviews test three things: coding knowledge, attention to detail, and problem-solving approach. Interviewers are looking for coders who can justify their code selection, not just assign codes from memory.

Fundamentals (Q1-Q10)

Q1: What is the difference between ICD-10-CM and CPT codes?

ICD-10-CM codes identify the patient's diagnosis — what is wrong (disease, injury, symptom, reason for visit). CPT (Current Procedural Terminology) codes identify what was done — the procedure or service provided (office visit, surgery, lab test, imaging). Every claim needs both: what was wrong and what was done.

Q2: What is a primary diagnosis vs a secondary diagnosis?

For inpatient (hospital): Primary diagnosis (also called principal diagnosis) is the condition established after study to be chiefly responsible for the admission. Secondary diagnoses are conditions that coexist at admission or develop subsequently that affect patient care. For outpatient: first-listed diagnosis is the primary reason for the visit.

Q3: What is unbundling and why is it problematic?

Unbundling is billing separately for services that should be included in one comprehensive code. Example: billing separate codes for each component of a comprehensive surgical package that has one inclusive CPT code. This is considered fraudulent billing and can result in audits, recoupments, and compliance violations.

ICD-10-CM Questions (Q11-Q20)

Q11: A patient is admitted with chest pain. After workup, they are diagnosed with GERD. What do you code?

Code the confirmed diagnosis GERD (K21.9) as the principal diagnosis. Do not code chest pain separately — it is the symptom that led to the diagnosis, and the guidelines say to code the definitive diagnosis when established.

Q12: A Type 2 diabetic patient is admitted for debridement of a diabetic foot ulcer. How do you code this?

Principal diagnosis: Diabetic foot ulcer with underlying condition — E11.621 (Type 2 diabetes mellitus with foot ulcer). Additional codes: the specific ulcer code (L97 range for non-pressure ulcer), and the debridement CPT code.

Q13: What is the 7th character extension in ICD-10-CM injury codes?

A = Initial encounter (active treatment phase). D = Subsequent encounter (routine care during healing). S = Sequela (complication or condition that arises as a direct result of the injury after healing is complete). These are mandatory for injury codes and many other categories. Missing or incorrect 7th characters are a common coding error.

CPT Questions (Q21-Q30)

Q21: What are the five levels of E/M office visit codes?

For established patients: 99211 (minimal), 99212 (straightforward), 99213 (low), 99214 (moderate), 99215 (high). Level is based on Medical Decision Making (MDM) complexity or total time spent. Since 2021 AMA revisions, the three key components (history, exam, MDM) were replaced by MDM alone OR total time as the basis for level selection.

Q22: What is a modifier? Give two examples.

A modifier is a two-digit code appended to a CPT code to provide additional information without changing the code's definition. Modifier 25: Significant, separately identifiable E/M service on the same day as a procedure — used when a physician performs a procedure and a separately documented E/M service. Modifier 59: Distinct procedural service — indicates a service is distinct from another on the same day.

Q23: What is the global surgical package?

A CPT surgical code includes pre-operative care (1 day before for major surgery), intraoperative services, and post-operative care (90 days for major procedures, 10 days for minor procedures). Billing separately for these services included in the global package is unbundling unless a modifier justifies it.

Compliance and Audit (Q31-Q40)

Q31: What is a Charge Capture audit?

Reviewing medical records to ensure all services provided were actually billed and coded correctly. Looks for both overcoding (billing for services not documented) and undercoding (failing to bill for services that were provided and documented).

Q32: What is the difference between upcoding and downcoding?

Upcoding: assigning a higher-level code than what the documentation supports to receive higher reimbursement — fraudulent. Downcoding: assigning a lower-level code than documented, often to avoid audit scrutiny — still incorrect coding and results in revenue loss.

Q33: What documentation do you look for to code an E/M visit?

Chief complaint, history of present illness (HPI), review of systems (ROS), past/family/social history (PFSH), physical examination findings, assessment and plan, medical decision making complexity, and time if billing by time. Since 2021 revisions, MDM and time are the primary determinants of E/M level.

See Healthcare Coding Academy for complete preparation guide.