ICD 10 Cheat Sheet 2026

The 30 highest-yield ICD 10 facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. In the Alphabetic Index, what do brackets [ ] around a code or term typically enclose? → Synonyms, alternative wording, or explanatory phrases
2. What does an Excludes1 note mean in the ICD-10-CM Tabular List? → The two conditions can never be coded together
3. What is the maximum number of characters an ICD-10-CM diagnosis code can contain? → 7
4. What is the most effective study strategy for this type of exam? → Consistent study over time using active recall, practice tests, and spaced repetition
5. A combination code in ICD-10-CM is best described as a single code that does what? → Classifies two diagnoses or a diagnosis with an associated complication
6. ICD-10-CM is primarily used in the United States for which purpose? → Diagnosis coding and reporting
7. Which POA indicator means the condition was present when the inpatient admission occurred? → Y
8. The instructional note 'Code first' in ICD-10-CM directs the coder to do what? → Sequence the underlying condition before the manifestation
9. A patient has a rash from a correctly prescribed and properly taken medication. How is this coded? → Code the rash first, then the T code for the drug's adverse effect
10. The following ICD-10 codes are used: → All of the above
11. Payment status indicator C in Medicare's Outpatient Prospective Payment System (OPPS) indicates that the HCPCS is: → Only performed in inpatient settings
12. When should you change an answer during exam review? → Only when you have a clear, specific reason to believe the original answer was wrong
13. Which root operation means cutting out or off a portion of a body part, without replacement? → Excision
14. Z codes for contact with and exposure to communicable diseases are found in which ICD-10-CM category? → Z20
15. Which character position in an ICD-10-CM code is reserved for the seventh-character extension such as encounter type? → Seventh
16. What is the difference between ICD-10-CM and ICD-10-PCS? → CM is for diagnosis coding; PCS is for inpatient procedure coding
17. A poisoning is documented but the intent is not stated. How should it be coded? → Accidental
18. The seventh-character 'A' in an injury code most commonly indicates which encounter type? → Initial encounter
19. External cause of morbidity codes in ICD-10-CM begin with which letters? → V, W, X, and Y
20. In MS-DRG terminology, what does 'MCC' stand for? → Major Complication or Comorbidity
21. Which coding principle requires assigning codes to the highest level of detail supported by the documentation? → Specificity
22. What does 'laterality' mean in ICD-10-CM coding? → Specifying which side of the body (right, left, or bilateral) is affected
23. Codes in the range C00–C96 in ICD-10-CM represent what type of condition? → Malignant neoplasms
24. Why does code T36.0X1A include the letter X in the fifth position? → It is a placeholder so the seventh character stays in position seven
25. What chapter covers diseases of the circulatory system? → Chapter 9 (I codes)
26. A patient returns for cast removal of a closed fracture that is healing routinely. Which seventh character applies? → D
27. How should you manage test anxiety? → Use preparation, deep breathing, positive self-talk, and arrive early to feel in control
28. A patient has hypertension and stage 3 chronic kidney disease (unspecified), with no heart disease documented. Which code set is correct? → I12.9 and N18.30
29. In the Medical and Surgical section of ICD-10-PCS, what does the 4th character represent? → Body part
30. Which of these is NOT a column in the ICD-10-CM Neoplasm Table? → Metastatic Recurrence