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🧠 Chapter 5: Mental, Behavioral & Neurodevelopmental Disorders

ICD-10-CM Codes F01–F99 | Your CPC Exam Master Guide

Your professor for today: Think of the F-code chapter as a filing cabinet with 10 drawers. Each drawer holds a family of disorders. Your job as a CPC coder isn't to diagnose — it's to code what the provider documented, to the highest specificity, and to sequence correctly.

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🗂️ THE BIG MAP — All 10 Drawers at a Glance

F01–F09  🧬  "Brain got BROKEN by something physical"
F10–F19  🍺  "Substances did the damage"
F20–F29  🌀  "Lost touch with reality"
F30–F39  😢😃  "Mood swings — high, low, or mixed"
F40–F48  😰  "Anxious, stressed, dissociated"
F50–F59  🍽️  "Body behaviors gone wrong"
F60–F69  🎭  "Personality & adult behaviors"
F70–F79  📉  "Intellectual disabilities"
F80–F89  🧩  "Developmental - wiring differences"
F90–F98  👶  "Kids & teens - behavior/emotions"
F99      ❓  "We know it's mental, but nothing else fits"

"Brain Substances Reality Mood Anxiety Body Personality Intellect Development Kids Unknown" B S R M A B P I D K U

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🧬 DRAWER 1: F01–F09 — Mental Disorders Due to Known PHYSIOLOGICAL Conditions

The Big Idea:

🔑 Key Codes You MUST Know:

🚨 CPC EXAM RULES for F01–F09:

• For F01 (vascular dementia): There will be a "Code first" instruction pointing to the underlying cerebrovascular disease
• For F02 (dementia in other diseases): "Code first" the underlying disease (e.g., Parkinson's G20, Huntington's G10)

Visual Example:

Patient has Parkinson's disease with dementia
WRONG:  F02.80 only
RIGHT:  G20 (Parkinson's) FIRST → then F02.80
        ↑ "Code first" instruction in ICD-10

• "Without behavioral disturbance" = patient is confused but calm
• "With behavioral disturbance" = patient is agitated, combative, wandering, or has other behavioral issues
• You need documentation of the behavioral issue to use the "with" code

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🍺 DRAWER 2: F10–F19 — Substance-Related Disorders

This is THE BIGGEST EXAM TOPIC in Chapter 5. Master this drawer cold.

The Substance Code Formula:

F [substance] . [severity] [complication]

F  10  .  1  2  0
│   │     │  │  └── complication subtype
│   │     │  └───── complication type
│   │     └──────── severity digit
│   └────────────── substance number
└────────────────── Chapter 5 / substance

Substance Numbers (F1X) — Memorize This Table:

Severity Digits (after the decimal):

.1x  =  ABUSE        (mild disorder)
.2x  =  DEPENDENCE   (moderate/severe disorder)
.9x  =  USE, unspecified (use sparingly - needs provider documentation)

Complication Digits (the last digit area):

🚨 THE MOST IMPORTANT SUBSTANCE RULES FOR CPC:

📌 KEY RULE: When same substance is documented as BOTH abuse AND dependence
              → Code DEPENDENCE only (it wins!)

📌 KEY RULE: Unspecified use (.9x) codes are RARE on the exam
              → Only assign when substance use is associated with
                a substance-related disorder AND provider documents it

• Mild disorder in remission → code as Abuse in remission (.11)
• Moderate/Severe disorder in remission → code as Dependence in remission (.21)
• NEVER assign "in remission" without provider documentation

Example: Patient has alcohol dependence causing alcoholic cirrhosis
SEQUENCE: K70.30 (alcoholic cirrhosis) FIRST
           F10.20 (alcohol dependence) SECOND
Because: the medical condition "code first" note takes priority

"Patient presents with cocaine dependence, uncomplicated. What code?" Answer: F14.20 (cocaine = F14, dependence = .2, uncomplicated = 0)

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🌀 DRAWER 3: F20–F29 — Schizophrenia & Psychotic Disorders

Key Codes:

Key Exam Tip:

• The "nonorganic" in F20–F29 means there is NO known physiological cause (contrast with F06 where there IS a physical cause)

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😢😃 DRAWER 4: F30–F39 — Mood (Affective) Disorders

The Mood Spectrum Visual:

MANIC POLE                              DEPRESSIVE POLE
    |___________________________|
    F30      F31         F32/F33
  Manic    Bipolar      Depression
 episode   disorder     (unipolar)

Critical Codes:

🚨 KEY EXAM DISTINCTIONS:

F32 = SINGLE EPISODE depression
F33 = RECURRENT depression (2 or more episodes)
         ↑
    THIS IS THE #1 CONFUSION POINT ON THE EXAM

F31 (Bipolar) specifiers you'll see:
  F31.0 = Bipolar I, current episode manic, unspecified
  F31.10-F31.13 = Bipolar I, current episode manic, various severities
  F31.30-F31.32 = Bipolar I, current episode depressed
  F31.81 = Bipolar II disorder ← High-yield exam code!

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😰 DRAWER 5: F40–F48 — Anxiety, Stress, Dissociative, Somatoform

High-Yield Codes for CPC:

🚨 THE PAIN RULE — Very Common on Exam:

F45.41 (pain purely psychological)
  → Excludes 1: G89 codes (cannot use both!)
  → If pain is ONLY psychological, use F45.41 ALONE

F45.42 (pain with psychological component)
  → USE WITH a G89 code
  → There IS a physical component too

PTSD Specificity Tip:

F43.10 = PTSD unspecified (no duration documented)
F43.11 = PTSD acute     (< 3 months)
F43.12 = PTSD chronic   (≥ 3 months)
                  ↑
       Code to highest specificity if duration is documented!

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🍽️ DRAWER 6: F50–F59 — Behavioral Syndromes / Physical Factors

Key: F55 is NOT a substance USE disorder - it's abuse of non-psychoactive stuff (laxatives, herbal remedies, vitamins)

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🎭 DRAWER 7: F60–F69 — Adult Personality & Behavior Disorders

Remember: Personality disorders = enduring, pervasive, inflexible patterns - not episodes

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📉 DRAWER 8: F70–F79 — Intellectual Disabilities

Memory Hook: "70-50-35-20 = Mild-Mod-Sev-Pro" → going DOWN the IQ, codes go UP

CPC Rule: Code first any associated physical or developmental condition. Also note: F70–F79 now have 4th character options for associated behavioral specifiers.

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🧩 DRAWER 9: F80–F89 — Pervasive & Specific Developmental Disorders

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👶 DRAWER 10: F90–F98 — Childhood & Adolescence Disorders

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🔑 MASTER CODING RULES FOR THE CPC EXAM

Rule #1 — Code to the HIGHEST SPECIFICITY

Never assign F41.9 (anxiety unspecified) if the documentation says "panic disorder"
Never assign F33.9 if the doc says "moderate recurrent depression"
ALWAYS look for the most specific code available

Rule #2 — "Code First" / "Use Additional Code" Instructions

These are MANDATORY sequencing instructions - they are law in ICD-10!

F01.xx → "Code first" underlying cerebrovascular disease
F02.xx → "Code first" underlying disease (Parkinson's, Huntington's, etc.)
Substance + Medical condition → the "Code first" note tells you which goes first

Rule #3 — The "With" Convention

In ICD-10-CM, "with" in a title or inclusion note = the coder can assume
the relationship exists WITHOUT needing the provider to explicitly link them.

Example: Alzheimer's disease with dementia
         → The "with" code covers both - ONE code, not two

Rule #4 — Substance Use Hierarchy

If patient has BOTH abuse and dependence of same substance:
  → Code DEPENDENCE (it supersedes abuse)

Mild SUD in remission → Abuse in remission code
Moderate/Severe SUD in remission → Dependence in remission code

Rule #5 — Z Codes as Additional Codes for Mental Health

Common Z codes paired with F codes on the CPC exam:

Z81.8 = Family history of mental disorder
Z86.59 = Personal history of mental disorder
Z91.5 = Personal history of self-harm
Z91.41 = Personal history of adult abuse

Rule #6 — Outpatient Coding vs. Inpatient

Outpatient: Code the CONFIRMED diagnosis (mental health diagnoses CAN be coded
            from outpatient documentation if the provider documents the condition)

Remember: You CAN code mental health conditions as confirmed diagnoses
          from outpatient visits - unlike uncertain conditions in other chapters

Rule #7 — F45.41 vs F45.42 vs G89 (Pain)

Pain ONLY from psychological factors    → F45.41 ALONE (no G89)
Pain with psychological component + pain → F45.42 + G89 code

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🧠 MEGA MNEMONIC — Chapter 5 Coding Laws

"SHADE"

• Specificity — always go to the highest detail
• Hierarchy — use/abuse/dependence - dependence wins
• Additional codes — "use additional code" notes are mandatory
• Documented — only code what the provider documented
• Excludes notes — respect Excludes 1 (never use both codes together)

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📊 TOP HIGH-YIELD CODES FOR 2026 CPC EXAM

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📝 CPC-LEVEL MCQ TEST — Chapter 5 (F01–F99)

Instructions: Answer each question as you would on the actual 2026 CPC exam. Use your ICD-10-CM knowledge. All questions are case-based or guideline-based - just like the real exam. Post your answers when ready!

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Post your answers below! I will grade every one, explain why each correct answer is right, and explain why the wrong answers are traps. Good luck - you've got this! 🎯

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Quick CPC tips about these chapters:

• The ICD-10-CM Official Guidelines (the book you use on the exam) has 4 Sections on top of the 21 chapters:
  • Section I - General coding conventions + Chapter-specific guidelines
  • Section II - Selection of principal diagnosis (inpatient)
  • Section III - Reporting additional diagnoses (inpatient)
  • Section IV - Diagnostic coding for outpatient services
• For the CPC exam, Section IV (Outpatient) is the most tested because CPC = professional/outpatient coding
• The chapters most heavily tested on the CPC for ICD-10 are: Chapters 2 (Neoplasms), 4 (Diabetes), 5 (Mental), 9 (Circulatory), 13 (Musculoskeletal), 19 (Injuries/Poisoning), and 21 (Z codes)

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🦠 Chapter 1: Certain Infectious & Parasitic Diseases

ICD-10-CM Codes A00–B99 | CPC Exam Master Guide

Your professor says: Chapter 1 has ONLY a few official guideline topics - but they are among the MOST tested on the entire CPC exam. HIV coding, Sepsis sequencing, and MRSA rules appear on nearly every exam. Master these three families and you own Chapter 1.

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🗂️ THE BIG MAP — Chapter 1 Code Blocks

A00–A09  🤢  Intestinal infections (food poisoning, cholera, salmonella)
A15–A19  💨  Tuberculosis (TB)
A20–A28  🐀  Zoonotic bacterial diseases (animal → human)
A30–A49  🦠  Other bacterial diseases (incl. SEPSIS A40-A41)
A50–A64  ❤️  Sexually transmitted infections (STIs) - NOT HIV
A65–A69  🌀  Spirochetal diseases (Lyme, syphilis variants)
A70–A74  🔬  Chlamydiae diseases
A75–A79  🐛  Rickettsioses (tick/flea-borne)
A80–A89  🧠  Viral CNS infections (polio, encephalitis)
A90–A99  🌡️  Arthropod-borne fevers (Dengue, Zika)
B00–B09  🔴  Viral skin/mucous membrane infections (herpes, pox)
B10–B10  🧬  Other human herpesviruses
B15–B19  🟡  Viral hepatitis (Hep A, B, C, D, E)
B20–B20  🎗️  HIV disease ← #1 EXAM TOPIC
B25–B34  🦠  Other viral diseases
B35–B49  🍄  Mycoses (fungal infections)
B50–B64  🦟  Protozoal diseases (malaria, toxoplasmosis)
B65–B83  🪱  Helminthiases (worms)
B85–B89  🐜  Infestations (lice, scabies)
B90–B94  📅  Sequelae of infectious diseases
B95–B97  🔬  Bacterial/viral agents (supplementary codes!) ← HIGH YIELD
B99       ❓  Other/unspecified infectious diseases

"H-S-M" = HIV + Sepsis + MRSA These three rule Chapter 1 on the CPC. Everything else is secondary.

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🎗️ BIG TOPIC #1 — HIV CODING (The Most Tested)

The HIV Code Universe — Just 5 Codes to Know:

┌─────────────────────────────────────────────────────────────┐
│                   HIV STATUS DECISION TREE                   │
│                                                             │
│  Patient has HIV...                                         │
│       │                                                     │
│       ├─ Symptomatic? Has ANY HIV-related illness?          │
│       │        └── YES → B20 (HIV disease)                 │
│       │                                                     │
│       ├─ Positive test but NO symptoms?                     │
│       │        └── YES → Z21 (asymptomatic HIV)            │
│       │                                                     │
│       ├─ Lab result inconclusive, no confirmed diagnosis?   │
│       │        └── YES → R75 (inconclusive HIV serology)   │
│       │                                                     │
│       ├─ Patient being SCREENED (no known HIV)?             │
│       │        └── YES → Z11.4 (screening for HIV)         │
│       │                                                     │
│       └─ Known exposure/contact but not infected?           │
│                └── YES → Z20.6 (contact/exposure to HIV)   │
└─────────────────────────────────────────────────────────────┘

The 5 HIV Codes - Memorized:

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🚨 HIV CODING RULES — Every Single One:

For ALL other diagnoses, inpatient coders can code "suspected" conditions.
For HIV: BOTH inpatient AND outpatient = confirmed ONLY.

Provider says "suspected HIV" or "possible HIV" → DO NOT code B20
Provider says "HIV positive" or "HIV disease" or "AIDS" → Code B20

This is an EXPLICIT EXCEPTION to normal inpatient coding rules. It WILL be tested.

Once a patient has been diagnosed with ANY HIV-related illness:
→ That patient is coded B20 on EVERY subsequent encounter
→ NEVER go back to Z21 or R75 after B20 has been established

SCENARIO A: Admitted FOR an HIV-related condition
    Sequence: B20 FIRST → then the HIV-related illness
    Example: B20, B59 (Pneumocystis pneumonia)

SCENARIO B: Admitted for UNRELATED condition, but also has HIV
    Sequence: The UNRELATED condition FIRST → then B20
    Example: S52.001A (broken arm) FIRST → then B20

SCENARIO C: HIV + Pregnancy (MOST CONFUSING!)
    Sequence: O98.7- (HIV complicating pregnancy) FIRST
              → then B20
              → then the HIV-related illness
    WHY: Chapter 15 (OB) ALWAYS has sequencing priority!

SCENARIO D: Asymptomatic HIV + Pregnancy
    Sequence: O98.7- FIRST → then Z21

You do NOT need a positive lab test.
Provider's written statement is sufficient:
  ✅ "HIV positive" → B20 (if symptomatic) or Z21 (if not)
  ✅ "has AIDS" → B20
  ✅ "HIV disease" → B20
  ❌ "possible HIV" → DO NOT CODE
  ❌ "probable HIV" → DO NOT CODE

Always assign B20 FIRST, then the specific opportunistic infection.
The tabular note under B20 says "Use additional code(s) to identify
all manifestations of HIV infection."

Example: HIV patient with Pneumocystis pneumonia
  → B20 + B59

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🔴 BIG TOPIC #2 — SEPSIS, SEVERE SEPSIS & SEPTIC SHOCK

The Sepsis Ladder — Visualized:

       ⬆ SEVERITY INCREASES ⬆

┌─────────────────────────────────────┐
│  SEPTIC SHOCK                       │  ← Circulatory failure
│  Severe sepsis + hypotension        │    Code: R65.21
├─────────────────────────────────────┤
│  SEVERE SEPSIS                      │  ← Sepsis + organ dysfunction
│  Sepsis + at least 1 organ failing  │    Code: R65.20 or R65.21
├─────────────────────────────────────┤
│  SEPSIS                             │  ← Infection + systemic response
│  Body-wide infection response       │    Code: A40.x / A41.x
├─────────────────────────────────────┤
│  LOCAL INFECTION                    │  ← Just infection, no systemic signs
│  UTI, pneumonia, wound, etc.        │    Code the infection alone
└─────────────────────────────────────┘

Key Sepsis Codes:

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🚨 SEPSIS SEQUENCING RULES — The Most Tested Rules in Chapter 1:

Sepsis alone → Code the INFECTION as principal diagnosis
Example: Patient admitted for sepsis due to E. coli UTI
  → A41.51 (sepsis due to E. coli) FIRST
  → N39.0 (UTI) as additional code

Minimum 3 codes required:
  1. Code for the underlying infection (A40.x/A41.x)
  2. R65.20 or R65.21 (severe sepsis)
  3. Code(s) for specific organ dysfunction

IMPORTANT: R65.2x can NEVER be the principal diagnosis!

Septic shock is a TYPE of organ dysfunction (circulatory failure).
Sequence:
  1. Systemic infection code (A41.x) FIRST
  2. R65.21 (severe sepsis with septic shock)
  3. Any other organ dysfunction codes

IMPORTANT: R65.21 can NEVER be principal diagnosis!
IMPORTANT: Septic shock code alone is NEVER enough - need infection code first!

Example: Trauma → leads to wound infection → develops sepsis
Sequence: NON-INFECTIOUS CONDITION (trauma) FIRST
           → then the infection/sepsis code
           → then R65.2x if severe sepsis present

If provider documents ONLY a local infection (UTI, pneumonia)
and does NOT document sepsis → DO NOT code sepsis
You cannot assume sepsis from lab values or clinical signs alone.
Only code sepsis when the provider explicitly documents it.

Sequence:
  1. Postprocedural infection code (T81.40-T81.43) FIRST
  2. T81.44 (sepsis following procedure)
  3. Code to identify the infectious agent
  4. R65.2x if severe sepsis present

Chapter 15 takes priority ALWAYS.
Sequence: O98.xx (or appropriate OB complication code) FIRST
           → then sepsis/infection codes

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Quick Visual — Sepsis Sequencing at a Glance:

SITUATION                          PRINCIPAL DX        SECONDARY
─────────────────────────────────────────────────────────────────
Just sepsis (no organ failure)     Infection code      Local site (if known)
Severe sepsis (organ failure)      Infection code      R65.20 + organ codes
Septic shock                       Infection code      R65.21 + organ codes
Sepsis from trauma/non-infectious  Non-infect. cause   Infection + R65.2x
Sepsis in pregnancy                OB code (O98.xx)    Infection code
Post-procedure sepsis              T81.40-T81.43       T81.44 + agent + R65.2x
Newborn sepsis                     See Chapter 16      (P36.x codes)

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🦠 BIG TOPIC #3 — MRSA & Antibiotic Resistance

The MRSA Code Toolkit:

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🚨 MRSA CODING RULES:

MRSA sepsis → Use A41.02 (it's already a combination code)
→ Do NOT separately add B95.62 when using A41.02

MRSA wound infection (no sepsis):
  → Code the INFECTION SITE (e.g., L03.011 cellulitis of right finger)
  → PLUS B95.62 (MRSA as the cause)
  → Do NOT add Z16.11 (resistance to penicillins) - guidelines explicitly say NO

Patient tested positive for MRSA but no active infection:
  → Z22.321 (carrier of MRSA)
  → This is different from active infection - colonization ≠ infection

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🔬 B95–B97 — THE SUPPLEMENTARY CODES (High Yield!)

B95.x = Streptococcus and Staphylococcus as the cause
B96.x = Other bacterial agents as the cause
B97.x = Viral agents as the cause

RULE: Use these when the infection code does NOT already include
      the causative organism in the combination code.

Example: UTI due to E. coli
  → N39.0 (UTI, unspecified)
  → B96.20 (E. coli as cause of disease classified elsewhere)

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📋 OTHER IMPORTANT CHAPTER 1 TOPICS

Tuberculosis (A15–A19):

• A15.0 = Pulmonary TB (lung — most common)
• A15.7 = Primary progressive TB
• A18.x = TB of other organs
• Always code the SITE of TB involvement
• "Code first" notes apply when TB affects organs in other chapters

Sequelae of Infections (B90–B94):

B90.x = Sequelae of TB
B91   = Sequelae of polio
B92   = Sequelae of leprosy
B94.x = Sequelae of other infectious diseases

Sequelae codes = LATE EFFECTS of an infection that is now resolved.
The original infection is gone, but the damage remains.

Zika Virus (A92.5):

• Code A92.5 for confirmed Zika
• Use Z20.821 for contact/exposure (no confirmed infection)
• In pregnancy, add code from Chapter 15 first

COVID-19 (U07.1) — Yes, it's in Chapter 1!

• U07.1 = Confirmed COVID-19
• U09.9 = Post-COVID condition (the lingering effects)
• These are listed with Chapter 1 in the official guidelines (even though U codes are technically supplementary)

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🔑 MASTER RULES SUMMARY FOR CHAPTER 1

┌────────────────────────────────────────────────────────────┐
│            THE CHAPTER 1 GOLDEN RULES                      │
├────────────────────────────────────────────────────────────┤
│ 1. HIV = CONFIRMED ONLY (no probable/suspected)            │
│ 2. Once B20, ALWAYS B20 (never go back to Z21)            │
│ 3. HIV + Pregnancy = O98.7- FIRST (OB always wins)        │
│ 4. B20 always before opportunistic infections              │
│ 5. Sepsis = infection code FIRST, never R65.2 first        │
│ 6. Severe sepsis = infection + R65.20 + organ dysfx codes  │
│ 7. Septic shock → infection FIRST, then R65.21             │
│ 8. MRSA sepsis = A41.02 alone (no separate B95.62)         │
│ 9. MRSA infection (no sepsis) = infection code + B95.62    │
│10. MRSA colonization ≠ infection → use Z22.321             │
│11. B95-B97 = SUPPLEMENTARY only, never stand alone         │
│12. Postprocedural sepsis → T81.40-T81.43 code FIRST       │
└────────────────────────────────────────────────────────────┘

Chapter 1 MEGA MNEMONIC — "COSC"

Confirmed only (HIV) Once B20 always B20 Sequence infection first (sepsis) Combination code for MRSA sepsis

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📊 TOP HIGH-YIELD CODES FOR CPC EXAM

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📝 CPC-LEVEL MCQ TEST — Chapter 1 (A00–B99)

Same rules as before - answer these like the real exam. Post your answers when done and I'll grade and explain each one!

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🎯 Post your 20 answers and I'll give you a full graded breakdown — score, correct answers, and explanations for every trap!

Also note: We'll be doing this for all 21 chapters. Next up when you're ready: Chapter 2 - Neoplasms (C00–D49) — which is one of the HEAVIEST tested chapters on the entire CPC exam! 💪

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🎗️ Chapter 2: Neoplasms

ICD-10-CM Codes C00–D49 | CPC Exam Master Guide

Your professor says: Chapter 2 is the HEAVYWEIGHT of the CPC exam. More sequencing questions come from here than almost any other chapter. The good news? It all boils down to ONE core skill: figuring out what to put first. Master the sequencing flowcharts below and you'll conquer this chapter.

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🗂️ THE BIG MAP — Chapter 2 Code Blocks

C00–C14   👄  Lip, oral cavity & pharynx (mouth cancers)
C15–C26   🫁  Digestive organs (esophagus, stomach, colon, liver, pancreas)
C30–C39   💨  Respiratory & intrathoracic (lung, trachea, bronchus)
C40–C41   🦴  Bone & articular cartilage
C43–C44   🟫  Skin (melanoma C43, other skin C44)
C45–C49   🧱  Soft tissue (mesothelioma, sarcomas)
C50        🎀  Breast ← HIGH YIELD
C51–C58   ♀️  Female genital organs (cervix, ovary, uterus)
C60–C63   ♂️  Male genital organs (prostate, testis)
C64–C68   💧  Urinary tract (kidney, bladder)
C69–C72   🧠  Eye, brain & CNS
C73–C75   🦋  Thyroid & endocrine glands
C76–C80   ❓  Ill-defined, secondary & unspecified sites
C7A        🔴  Malignant neuroendocrine tumors (carcinoids)
C7B        🔴  Secondary neuroendocrine tumors
C81–C96   🩸  Lymphoid & hematopoietic (lymphoma, leukemia, myeloma)
D00–D09   🔶  IN SITU neoplasms
D10–D36   🟢  BENIGN neoplasms
D3A        🟢  Benign neuroendocrine tumors
D37–D48   🟡  UNCERTAIN behavior
D49        ⬜  UNSPECIFIED behavior

"MIBUU" = Malignant · In-situ · Benign · Uncertain · Unspecified

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📊 STEP 1 — How to CODE Any Neoplasm (The 3-Step Process)

STEP 1: What BEHAVIOR is it?
         Malignant? In-situ? Benign? Uncertain? Unspecified?
              ↓
STEP 2: Is the malignancy PRIMARY or SECONDARY?
         (Where did it START vs. where did it SPREAD?)
              ↓
STEP 3: What is the exact SITE?
         (Use the Neoplasm Table in the Alphabetic Index)

The Neoplasm Table — How It Works:

The Neoplasm Table in your ICD-10-CM Index is organized like this:

SITE              | Malignant | Malignant  | Ca in  | Benign | Uncertain | Unspecified
                  | Primary   | Secondary  | Situ   |        | Behavior  | Behavior
──────────────────┼───────────┼────────────┼────────┼────────┼───────────┼────────────
Breast            | C50.xxx   | C79.81     | D05.xx | D24.x  | D48.6x    | D49.3
Lung              | C34.xx    | C78.0x     | D02.2x | D14.3x | D38.1     | D49.1
Colon             | C18.x     | C78.5      | D01.0  | D12.x  | D37.4     | D49.0

CPC Tip: Always go to the INDEX first for neoplasm terms, then verify in the Tabular. For descriptive terms like "carcinoma," "adenocarcinoma," "sarcoma" - look them up in the INDEX, which will point you to the Neoplasm Table.

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🔑 THE MASTER SEQUENCING FLOWCHART

┌─────────────────────────────────────────────────────────────────┐
│         WHAT IS THE REASON FOR THE ENCOUNTER?                   │
├─────────────────────────────────────────────────────────────────┤
│                                                                  │
│  ① Treating the PRIMARY cancer                                  │
│     → Primary cancer FIRST                                      │
│       + secondary site(s) after                                 │
│                                                                  │
│  ② Treating a SECONDARY (metastatic) site ONLY                  │
│     → Secondary site FIRST                                       │
│       + primary cancer after                                     │
│                                                                  │
│  ③ Chemo / Radiation / Immunotherapy visit                      │
│     → Z51.11 / Z51.12 / Z51.0 FIRST                            │
│       + neoplasm code after                                      │
│     EXCEPTION: Surgical removal at same time                    │
│     → Neoplasm code FIRST (not Z51)                             │
│                                                                  │
│  ④ Complication OF the neoplasm (e.g., anemia, dehydration)     │
│     → PRIMARY neoplasm FIRST                                     │
│       + complication code after                                  │
│                                                                  │
│  ⑤ Complication OF the TREATMENT (e.g., chemo nausea)          │
│     → Z51.11 (chemo) FIRST                                      │
│       + adverse effect code + neoplasm after                    │
│                                                                  │
│  ⑥ Surgical COMPLICATION (e.g., post-op infection)             │
│     → The COMPLICATION code FIRST                               │
│       + neoplasm after                                           │
│                                                                  │
│  ⑦ Neoplasm in PREGNANCY                                        │
│     → O9A.1x (malignant neoplasm complicating pregnancy) FIRST  │
│       + Chapter 2 neoplasm code after                           │
│                                                                  │
│  ⑧ Anemia DUE TO neoplasm                                       │
│     → Neoplasm code FIRST                                        │
│       + D63.0 (anemia in neoplastic disease) after              │
│                                                                  │
│  ⑨ Anemia DUE TO chemo/radiation (not the cancer itself)       │
│     → Z51.11/Z51.12 FIRST (treatment visit)                     │
│       + neoplasm + D64.81 (anemia due to antineoplastic drugs)  │
└─────────────────────────────────────────────────────────────────┘

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🎯 PRIMARY vs. SECONDARY — Never Confuse These Again

PRIMARY = Where cancer STARTED (the original tumor site)
          Codes: C00–C75, C7A, C81–C96

SECONDARY = Where cancer SPREAD TO (metastasis)
            Codes: C77.x–C79.x (and C7B)

                ┌────────────┐
                │ LUNG CANCER │  ← PRIMARY (C34.xx) - started here
                └────────────┘
                       ↓ spreads to
         ┌─────────────┬─────────────┐
         ▼             ▼             ▼
      C77.0         C78.7         C79.51
   Lymph nodes    Liver mets    Bone mets
   (secondary)   (secondary)   (secondary)

KEY EXAM TRAP: Just because a cancer is found in the LIVER does not make it a primary liver cancer. If the primary is in the lung and it spread to the liver, the liver lesion is C78.7 (secondary malignant neoplasm of liver) - NOT a primary liver cancer.

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🟢 THE 5 BEHAVIOR TYPES — Detailed

1. Malignant Primary (C00–C75, C7A, C81–C96)

• Invasive cancer that STARTED at this site
• Has potential to spread (metastasize)
• Most CPC questions involve these

2. Malignant Secondary (C77–C79, C7B)

• Cancer that SPREAD FROM somewhere else (metastasis)
• C77.x = Secondary in lymph nodes
• C78.x = Secondary in respiratory/digestive organs
• C79.x = Secondary in other/unspecified sites

3. In Situ (D00–D09)

• Cancer cells present BUT have not invaded surrounding tissue yet
• "Pre-invasive" — the cancer is contained
• Examples: CIN III → D06.x (cervical), DCIS → D05.x (breast)

4. Benign (D10–D36, D3A)

• Non-cancerous, does NOT invade or spread
• Examples: lipoma, fibroma, adenoma

5. Uncertain Behavior (D37–D48)

• Path report says the behavior cannot be determined
• NOT the same as "unspecified" — this means the pathologist genuinely can't tell
• Use these ONLY when the pathology report says uncertain

6. Unspecified Behavior (D49)

• Provider documented a neoplasm but gave NO information on benign vs malignant
• Last resort — use only when no other info available

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📘 KEY GUIDELINE TOPICS IN DETAIL

A — Primary Malignancy Previously Excised

SITUATION 1: Excised + still receiving treatment (chemo/radiation)
  → STILL use the C-code (primary cancer code)
  → It's still being "treated" even if removed

SITUATION 2: Excised + NO further treatment + NO evidence of disease
  → Switch to Z85.x (Personal history of malignant neoplasm)
  → The cancer is GONE - only history remains

THE MAGIC QUESTION: "Is there still active treatment directed to that site?"
  YES → C-code
  NO  → Z85-code

Memory Hook: "C = Current, Z85 = Zero cancer now"

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B — Leukemia / Multiple Myeloma / Plasma Cell Neoplasms (Special Rule)

These cancers have "in remission" codes built RIGHT INTO the C-code.
Don't jump to Z85 just because a patient is in remission!

C91.01 = Acute lymphoblastic leukemia, IN REMISSION
C92.01 = Acute myeloid leukemia, IN REMISSION

Z85.6  = Personal history of leukemia (use ONLY when truly cured/no treatment)

KEY: If documentation is unclear whether in remission or personal history
     → QUERY THE PROVIDER

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C — Functional Activity

Some neoplasms produce hormones or other substances.
Example: Adrenal pheochromocytoma producing excess adrenaline
         Carcinoid tumor producing serotonin

Rule: Code the neoplasm FIRST
      Then ADDITIONALLY code the functional activity (usually Chapter 4)

Example:
  C74.10 (malignant neoplasm of adrenal gland) +
  E27.5 (adrenomedullary hyperfunction) ← functional activity

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D — Overlapping Sites

When a neoplasm overlaps 2 adjacent sites and cannot be classified to either:
→ Use code ending in ".8" (overlapping lesion)

Example: Cancer of lower and middle third of esophagus
  → C15.8 (overlapping lesion of esophagus)

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E — Contiguous vs. Non-Contiguous Sites

Contiguous = tumors NEXT to each other, overlapping
  → May use the ".8" overlapping code

Non-contiguous = separate tumors in NON-adjacent sites
  → Code EACH site separately

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F — Z Codes Paired with Neoplasms

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G — Anemia and Neoplasms — TWO Scenarios (Very Tested!)

SCENARIO 1: Anemia IS DUE TO the cancer itself
  Principal DX: Neoplasm code (C-code) FIRST
  Secondary:    D63.0 (anemia in neoplastic disease)

SCENARIO 2: Anemia is due to CHEMO/RADIATION (not the cancer)
  Principal DX: Z51.11 (chemo encounter) FIRST
  Secondary:    Neoplasm code + D64.81 (anemia due to antineoplastic drugs)

The KEY Question: What caused the anemia — the cancer or the treatment?

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H — C80.1 — The "Cancer, Unspecified" Code

C80.1 = Malignant (primary) neoplasm, unspecified

WHEN TO USE:
  → Provider confirms malignancy but origin site CANNOT be determined
  → Cancer of UNKNOWN primary (CUP)

WHEN NOT TO USE:
  → Do NOT use if the primary site is documented
  → RARELY used in inpatient settings (almost never)
  → Never use just because the coder doesn't know - the PROVIDER must state
    that the primary site cannot be determined

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I — Secondary Sites C77–C79 Reference Table

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🔑 MASTER RULES SUMMARY — Chapter 2

┌────────────────────────────────────────────────────────────────┐
│                 CHAPTER 2 GOLDEN RULES                         │
├────────────────────────────────────────────────────────────────┤
│  1. Treating PRIMARY → primary C-code FIRST                    │
│  2. Treating SECONDARY ONLY → secondary C7x FIRST             │
│  3. Chemo/Rad visit → Z51.11/Z51.0 FIRST (unless surgery too) │
│  4. Surgery + chemo same episode → neoplasm FIRST             │
│  5. Anemia due to cancer → cancer FIRST + D63.0               │
│  6. Anemia due to chemo → Z51.11 FIRST + D64.81               │
│  7. Still being treated → C-code (even if tumor was removed)  │
│  8. No more treatment + no evidence → Z85.x                   │
│  9. Leukemia in remission → built-in C-code (NOT Z85)         │
│ 10. Pregnancy + neoplasm → O9A.1x FIRST (OB always wins)      │
│ 11. Neoplasm complication → neoplasm FIRST + complication      │
│ 12. Surgical complication → complication FIRST + neoplasm      │
│ 13. Functional activity → neoplasm + Chapter 4 code           │
│ 14. Unknown primary site → C80.1 (only if provider confirms)  │
│ 15. OB + chemo complication → Z codes may sequence differently │
└────────────────────────────────────────────────────────────────┘

Chapter 2 MEGA MNEMONIC — "PAST"

Primary first (unless treating secondary only) Anemia — ask what CAUSED it (cancer or chemo?) Still treating = C-code; Stopped + gone = Z85 Treatment visit (chemo/rad) = Z51 first

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📊 TOP HIGH-YIELD CODES FOR CPC EXAM

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📝 CPC-LEVEL MCQ TEST — Chapter 2 (C00–D49)

Same format as before. Answer all questions and post your answers when ready — I'll grade and explain every one!

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🎯 Post your answers — I'll grade every single one with full explanations!

✅ Series progress: Chapter 1 ✔ | Chapter 2 ✔ | Up next: Chapter 3 — Blood & Blood-Forming Organs (D50–D89) whenever you're ready!