CCDS Acute Kidney Injury and Renal Documentation 5 — Questions and Answers
Question 1: A patient on vancomycin for MRSA bacteremia develops creatinine rise from 0.8 to 2.1 mg/dL. The physician documents 'drug-induced nephropathy.' What additional documentation should the CDS seek?
- The specific drug name and whether it is an adverse effect or poisoning (Correct answer)
- Only the vancomycin trough levels
- Documentation of the MRSA source only
- Whether the patient has underlying CKD
Correct answer: The specific drug name and whether it is an adverse effect or poisoning
Accurate coding requires identifying the specific causative drug and classifying the encounter as an adverse effect (drug taken correctly) versus a poisoning or underdosing, as this affects the T-code selection paired with the nephropathy code.
Question 2: Which clinical scenario best supports documentation of 'pre-renal AKI' for coding and clinical purposes?
- Creatinine rise following administration of IV contrast dye
- BUN/Cr ratio >20:1 with rapid creatinine normalization after IV fluid resuscitation (Correct answer)
- Proteinuria >3.5 g/day with hypoalbuminemia
- Rising creatinine with white cell casts on urinalysis
Correct answer: BUN/Cr ratio >20:1 with rapid creatinine normalization after IV fluid resuscitation
A BUN-to-creatinine ratio >20:1 combined with prompt creatinine normalization following fluid administration is the hallmark clinical picture of pre-renal AKI due to volume depletion or reduced renal perfusion.
Question 3: A CDS review identifies that a patient had continuous renal replacement therapy (CRRT) for 4 days but the record only documents 'electrolyte management.' What is the appropriate CDS action?
- Code CRRT as a procedure without querying for the clinical indication
- Query the physician to document the reason for CRRT and whether AKI or CKD Stage 5 was the indication (Correct answer)
- Document acute renal failure based on the CRRT use alone
- Add a note that CRRT was performed and close the review
Correct answer: Query the physician to document the reason for CRRT and whether AKI or CKD Stage 5 was the indication
CRRT is a significant procedure that requires physician documentation of the clinical indication (typically AKI Stage 3 or ESRD) to support accurate diagnosis coding and appropriate DRG assignment.
Question 4: Under the Uniform Hospital Discharge Data Set (UHDDS) guidelines, when should AKI be coded as a secondary diagnosis?
- Only when it is the primary reason for admission
- When it affects patient care, requires clinical evaluation, or prolongs the length of stay (Correct answer)
- Only when dialysis is performed during the encounter
- When the physician lists it in the problem list but not the discharge summary
Correct answer: When it affects patient care, requires clinical evaluation, or prolongs the length of stay
UHDDS defines additional diagnoses as conditions that affect patient care in terms of requiring clinical evaluation, therapeutic treatment, diagnostic procedures, extended length of stay, or increased nursing care and monitoring.
Question 5: A patient is admitted with AKI and recovers renal function before discharge. The discharge summary states 'resolved AKI.' How should this be coded?
- Do not code AKI since it resolved before discharge
- Code AKI as a secondary diagnosis because it was present and treated during the encounter (Correct answer)
- Code only the underlying cause of the AKI
- Code as history of AKI using a Z code
Correct answer: Code AKI as a secondary diagnosis because it was present and treated during the encounter
Conditions that are diagnosed and treated during the hospitalization are coded even if resolved at discharge, as they affected patient care and management during the encounter.
Question 6: Which laboratory finding, when documented by the physician as clinically significant, most directly supports querying for hyperkalemia as a complication of AKI?
- Serum potassium of 3.2 mEq/L with muscle cramps
- Serum potassium of 6.1 mEq/L with peaked T-waves on ECG (Correct answer)
- Serum sodium of 128 mEq/L with confusion
- BUN of 45 mg/dL with nausea
Correct answer: Serum potassium of 6.1 mEq/L with peaked T-waves on ECG
A serum potassium of 6.1 mEq/L with ECG changes represents clinically significant hyperkalemia, a known complication of AKI due to impaired renal potassium excretion, warranting physician documentation and separate coding.
Question 7: When a patient with documented AKI Stage 2 does not recover baseline renal function at discharge and is discharged with a GFR of 28 mL/min, what documentation should the CDS query for?
- Whether the patient now meets criteria for CKD and at what stage (Correct answer)
- Only the cause of the initial AKI
- Whether dialysis should be initiated as outpatient
- The patient's outpatient follow-up plan only
Correct answer: Whether the patient now meets criteria for CKD and at what stage
When AKI does not fully resolve, the physician should document whether the patient has developed or worsened CKD, as a GFR of 28 mL/min corresponds to CKD Stage 4 and would be coded alongside AKI to reflect the transition from acute to chronic kidney disease.
CCDS Acute Kidney Injury and Renal Documentation 5
A patient on vancomycin for MRSA bacteremia develops creatinine rise from 0.8 to 2.1 mg/dL.
The physician documents 'drug-induced nephropathy.' What additional documentation should the CDS seek?