Mast Cell Activation Syndrome denials in California external review

In the California DMHC record, independent physician reviewers decided 17 published external-review cases involving mast cell activation syndromeand overturned the plan’s denial in 41.2%. That is a historical result among cases that reached this program, not a forecast for an individual appeal.

California DMHC decisions
17
2019–2026
Overturned
41.2%
7 denials reversed

What the insurer actually argued

Denials fall into different categories, and they don’t succeed equally — so the reason on your letter changes how you should answer it.
Reason givenDecisionsOverturned
Medical Necessity
The plan said the care wasn’t medically necessary. The most common fight, and the most winnable.
14
42.9%
Experimental/Investigational
The plan called the treatment unproven. These turn on published evidence, so the appeal is a literature argument.
3
33.3%
Typical time to a decision
9 days
Most land between 5 and 20 days
Handled as urgent
64.7%
Expedited when a delay would cause harm

What the reviewers wrote

Excerpts from the independent reviewers’ published findings — the actual reasoning, quoted, not summarised.

Where the denial was overturned

Findings: The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for mast cell infusion regimen composed of slow infusion of 2 liters normal saline, then additional medications including low dose diphenhydramine, ondansetron, famotidine, diphenhydramine, and ketorolac once every 30 to 45 minutes over 4 to 5 hours, including office visit, normal saline infusion, infusion supplies including pump, diphenhydramine, ondansetron, famotidine, diphenhydramine, ketorolac, and intravenous push and infusion services.The records document diagnoses of mast cell activation syndrome and small intestinal bacterial overgrowth. The treating provider recommended infusion therapy including diphenhydramine, diazepam, ondansetron, and famotidine.
Experimental/Investigational · 2026 · IMR EI26-46756
Nature of Statutory Criteria/Case Summary: The patient has requested authorization and coverage for Xolair Findings: A study notes that mast cell activation syndrome (MCAS) is defined by typical clinical symptoms such as urticaria, pigmentosa, unexplained hypotension, flushing, organomegaly, a substantial transient increase in serum tryptase level or an increase in other mast-cell-derived mediators, and a response of clinical symptoms to agents that attenuate the production of mast-cell-derived mediators. MCAS may present with skin, gastrointestinal, cardiovascular, respiratory and neurologic symptoms.
Medical Necessity · 2022 · IMR MN22-36675

Where the denial was upheld

Worth reading too — these show what an appeal has to overcome.
Nature of Statutory Criteria/Case Summary: An enrollee has requested authorization and coverage for Shoemaker Protocol including office visit with qualified provider experienced with the Shoemaker Protocol once every four to six weeks until the Shoemaker Protocol is completed; Welchol 625 mg; liposomal vitamin C 500 mg; vasoactive intestinal peptide nasal spray; epinastine HCL 0.05% two drops twice daily; neuroquadrant magnetic resonance imaging (MRI) without contrast; macron biofilm analysis; nares culture; Singulair 10 mg once daily; Cromolyn 4 ampules twice daily; and cholestyramine non-saccharine 4 grams. CRIS is a controversial constellation of symptoms, which is not currently accepted as a diagnostic disorder.
Experimental/Investigational · 2020 · IMR EI20-32594
Nature of Statutory Criteria/Case Summary: An enrollee has requested authorization and coverage for IVIG therapy.The submitted clinical documentation does not support that IVIG therapy is medically necessary for the patient. There are no visit notes demonstrating how diagnoses of mast cell activation syndrome (MCAS), Ehlers-Danlos syndrome or postural hypotension syndrome (POTS) were made. All of the patient’s submitted mast cell studies were normal and the records fail to demonstrate evidence of mast cell activation syndrome.
Medical Necessity · 2019 · IMR MN19-31282

Figures and quotations on this page come from 42,749 published decisions in the California DMHC Independent Medical Review dataset. These are California external-review outcomes. Other state and federal programs have different eligibility rules, processes, and current availability; the rates here do not transfer to those programs or predict an individual result. Excerpts are quoted verbatim from the public record and describe this condition generally, not any individual case.

How to use this in your appeal

These outcomes describe eligible cases completed through California DMHC’s Independent Medical Review program. They do not estimate the chance that an internal appeal, an external review in another jurisdiction, or your individual case will succeed. Use the record to identify evidence patterns involving mast cell activation syndrome, then check the rights and deadlines that apply to your plan.

SOURCE: CALIFORNIA DMHC INDEPENDENT MEDICAL REVIEW OUTCOMES (CHHS OPEN DATA) · AGGREGATES + DEIDENTIFIED DECISION EXCERPTS/REFERENCE IDS · METHODOLOGY

Not legal or medical advice. Coverage Rights is a self-help tool that helps you prepare your own appeal. For advice about your specific situation, talk to a licensed attorney or your doctor.

Fighting a denial for mast cell activation syndrome? Use the California record to prepare.

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