Appeal type: Inpatient Hospital
Decision: Unfavorable

 
We decided that the Plan does not have to pay for inpatient hospital services provided on September 21, 2022, 
to September 24, 2022, at the Diagnosis Related Group (DRG) originally billed. 
 
You asked the Plan to pay for the inpatient hospital services at the DRG originally billed. You say that the 
assignment of the original diagnoses billed is valid. The Plan denied your request. The Plan says the submitted 
medical record do not clinically validate the diagnoses of G92.8 acute toxic metabolic encephalopathy or N17.9 
acute kidney failure. Removal of these diagnoses resulted in a lower DRG being paid. 
 
The Plan must follow Medicare rules. Medicare rules say that providers must report services correctly. 
Providers must report inpatient hospital services with the appropriate DRG, which is based, in part, on the 
reported principal and secondary diagnosis codes.   
 
In this case, you billed the inpatient services provided with diagnoses of G92.8 acute toxic metabolic 
encephalopathy or N17.9 acute kidney failure. We asked our physician reviewer to carefully review the case 
file and apply the relevant Medicare rules to determine if the Plan was correct in denying the request to pay for 
the inpatient hospital services at the DRG originally billed. Our reviewer says that the diagnoses of G92.8 acute 
toxic metabolic encephalopathy or N17.9 acute kidney failure are not supported by the medical record. Our 
physician reviewer found that for acute toxic encephalopathy, this diagnosis requires a change in mental status 
which is beyond baseline that would not be easily explained by another neurocognitive disorder.  During this 
hospital stay, documentation does not support change in mental status to support the diagnosis code.  Provider 
documentation describes the patient being awake, alert and oriented.  Per National Library of Medicine "A 
diagnosis of toxic encephalopathy can be made after documentation of the following: 1) a sufficiently intense 
or prolonged exposure to the neurotoxin; 2) a neurological syndrome appropriate for the putative neurotoxins; 
3) evolution of symptoms and signs over a compatible temporal course; and 4) exclusion of other neurological 
disorders that may account for a similar syndrome".  Therefore, the documentation submitted does not include 
documentation to support this diagnosis. For the diagnosis of N17.9, the criteria for Acute Kidney Failure 
(AKF) is referenced by the National Kidney Foundation.  Those criteria are is as follows: "Increases SCr to 3 
baseline; or an increase of 0.5 mg/dL to a value of 4 mg/dL; and Urine output 0.3 mg/kg/h for 12 h or anuria 
for 12 h". Although, AKF is documented in the medical record, criteria is not supported, and therefore cannot 
be verified.    
 
We looked at this physician's review, the file, and Medicare rules. Based on this information, we decided the 
medical records do not substantiate the DRG as billed. Therefore, we decided that the Plan does not have to pay 
for inpatient hospital services provided on September 21, 2022, to September 24, 2022, at the Diagnosis 
Related Group (DRG) originally billed.