Certified Medical Coding Specialist Case Studies & Practical Application 4 — Questions and Answers
Question 1: A patient is admitted for a planned right total knee arthroplasty. Postoperatively, the patient develops a pulmonary embolism. How is the PE coded?
- As the principal diagnosis since it was the most serious complication
- As a secondary diagnosis since the TKA was the planned reason for admission (Correct answer)
- Not coded since it is a complication of surgery
- As a postoperative complication code with the TKA as secondary
Correct answer: As a secondary diagnosis since the TKA was the planned reason for admission
The total knee arthroplasty remains the principal diagnosis; the postoperative PE is coded as a secondary complication (I26.xx) along with a complication code if applicable.
Question 2: A physician documents removal of a 1.5 cm malignant lesion from the face with a 0.5 cm margin on each side. What diameter is used to select the excision code?
- 1.5 cm — the lesion diameter only
- 2.5 cm — lesion plus one margin (Correct answer)
- 2.0 cm — lesion plus total margin on one side
- 3.5 cm — total tissue removed
Correct answer: 2.5 cm — lesion plus one margin
CPT guidelines require adding the widest diameter of the lesion plus the narrowest margin on each side, so 1.5 + 0.5 + 0.5 = 2.5 cm is used for code selection.
Question 3: A patient with stage III chronic kidney disease (CKD) is also hypertensive. Per ICD-10-CM, how is this coded?
- Separately: I10 and N18.3
- With the combination code I12.9 and N18.3 (Correct answer)
- With only I10 since hypertension causes CKD
- With only N18.3 since CKD is the more specific diagnosis
Correct answer: With the combination code I12.9 and N18.3
ICD-10-CM presumes a cause-and-effect relationship between hypertension and CKD; the combination code I12.9 (hypertensive CKD) plus N18.3 (stage III) are assigned.
Question 4: A patient undergoes a bilateral diagnostic mammogram. The CPT code 77067 is reported. A radiologist reviews and interprets the images separately. How is the interpretation billed?
- Included in 77067; no separate code is needed
- With modifier -26 appended to 77067 (Correct answer)
- With modifier -TC appended to 77067
- With a separate CPT code for the professional component only
Correct answer: With modifier -26 appended to 77067
Modifier -26 designates the professional component (interpretation and report) when the physician bills separately from the facility that owns the equipment.
Question 5: A coder reviews a record where the physician used the term 'alcoholic cirrhosis.' Which ICD-10-CM code is most appropriate?
- K74.60 — unspecified cirrhosis
- K70.30 — alcoholic cirrhosis of liver without ascites (Correct answer)
- K70.10 — alcoholic hepatitis
- K74.69 — other cirrhosis of liver
Correct answer: K70.30 — alcoholic cirrhosis of liver without ascites
K70.30 specifically captures alcoholic cirrhosis of the liver without ascites, reflecting the physician's documentation of the etiology.
Question 6: An encounter note states the patient is a 28-year-old pregnant woman at 32 weeks gestation seen for supervision of a normal pregnancy. Which code is reported?
- Z34.32 — encounter for supervision of normal pregnancy, third trimester (Correct answer)
- O09.529 — supervision of elderly primigravida, unspecified trimester
- Z34.02 — encounter for supervision of normal first pregnancy, second trimester
- Z34.32 is incorrect; use O80 for normal delivery
Correct answer: Z34.32 — encounter for supervision of normal pregnancy, third trimester
Z34.32 is the correct code for supervision of a normal pregnancy in the third trimester (weeks 28–40).
Question 7: A surgeon performs a complex repair of a 4.5 cm laceration of the neck and a simple repair of a 2.0 cm laceration of the arm during the same encounter. How are these coded?
- Code both repairs separately using appropriate CPT codes (Correct answer)
- Code only the complex repair since it is the more complex procedure
- Add the lengths together and code one repair code for 6.5 cm
- Code the complex repair and append modifier -51 to the simple repair
Correct answer: Code both repairs separately using appropriate CPT codes
Repairs of different complexity (simple vs. complex) at different anatomic sites are coded separately with their respective CPT codes.
Certified Medical Coding Specialist Case Studies & Practical Application 4
A patient is admitted for a planned right total knee arthroplasty.
Postoperatively, the patient develops a pulmonary embolism.
How is the PE coded?