Metabolic Acidosis

edited February 2019 in Denials

We received a denial on metabolic acidosis. Based on the review of the medical record, this dx was not clinically validated. Based on the insurance company criteria for metabolic acidosis:

Arterial serum pH reduced to less than 7.35 and serum bicarbonate concentration is abnormally low, often defined as less than 22 mEg/L (although the threshold may vary across laboratories)

Patient presented to the hospital with abdominal pain, nausea and vomiting due to SBO. Lactate level 2.9, no bicarbonate level less than 22 and no pH from ABG's less than 7.35. HCO3 remained at 24 during the hospital stay, no ABG's done. Lactate decreased to 2.1 approx. 7 hours after admission. No bicarb given, no additional monitoring noted.

Patient was treated with IVF's (D5 1/2NS with KCL) during the admission. Of note patient's Anion gap was 15.4

Question: Our supervisor is trying to flight/appeal this denial, because the CDI nurse that reviewed the chart is saying that this patient clearly has metabolic acidosis. Any thoughts on how this should be handled to flight/appeal the denial?... Any alternate criteria with tx to counter the criteria/tx the insurance company is giving?


  • I have had denials similar to this.  Sometimes the reviewers are hung up on the anion gap with metabolic acidosis.  With lactic acidosis appeals, I include the coding decision pathway to show that the mainterm was acidosis, subterm lactic and the final code assignment.  I pull in treatment, hopefully a bolus in ED and any other conditions that may be linked, i.e. AKI, dehydration etc.  Just depends on the auditor's criteria
  • HCO3 is 24 - sounds like the patient is compensated and not acidotic, despite the stated gap - if pH does not reflect acidic state, there is no acidosis.  Per our clinical advisors, elevated lactate alone in a patient with compensation reflects abnormal lactate levels, but not ‘acidosis’ unless there is other supporting evidence.

    Paul Evans, RHIA
  • I respectfully disagree with Paul's comment of "if the pH does not reflect acidic state, there is no acidosis".

    I'm new to the platform and not sure if this will be read but I feel it's worth a shot as I'm dealing with a similar (yet different) denial in which a patient had a low HCO3 but no blood gas was collected. The payer is denying metabolic acidosis because there was no pH to support the diagnosis. I've argued that the pH is obsolete and not necessary to diagnose metabolic acidosis (see below).

    Metabolic acidosis is a process that decreases the bicarb (HCO3) concentration. Acidemia (as opposed to acidosis) is defined as a low pH. Not all patients with metabolic acidosis have acidemia - thus, the pH in a patient with metabolic acidosis may be low, high or normal. Most providers are taught this in their first year of medical school.

    I don't feel like providers should be required to order unnecessary blood gases (ABGs or VBGs) on patients to assess the pH to diagnose someone with acidosis. I'm not sure why a payer would deny metabolic acidosis without a pH as it is not part of the diagnostic criteria.

    Am I missing something? Has anyone else dealt with this?

  • In the scenario provided, the poster states an ABG was performed and the pH was not less than 7.35. You bring an interesting point and I am following to see what other thoughts can be brought to the table. However, the situation you describe in which no ABG was performed is different that the case in question, in which an ABG was performed with a pH not reflective of acidosis.

    Perhaps my point is flawed, but I was taught not to query for acidosis if the patient is compensated and the pH is not in an acidotic range?

    The original poster is discussing metabolic acidosis, not ‘lactic’ acidosis. I should have stated I would not query for METABOLIC acidosis with the pH levels cited, as it seems the patient is not acidotic , and is compensated.

    It should also be noted the original poster states ‘no bicarbonate given, and no additional monitoring provided”?

    It seems the condition did not satisfy for reporting as a secondary condition?

    I would have to understand why the patient may have been acidotic and would also confirmed any acid disorder coded reflected more than one lab value? How may were there? Again, and importantly, how were the UHDDS criteria for reporting met?

    I think this conversation affirms that medical staff approved definitions are vital.

    Following with interest….

    Thanks, Paul

  • What is causing any acid/base issues?

    Is acidosis inherent to the underlying cause of any acidosis?

    What was done about the acidosis?

    An auditor might question based on any of the 3 issues above.

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