Appeal win rates · California

Transplants, anesthesia and hyperbaric oxygen: 42% of denials overturned

Since 2021, independent doctors reviewed 122 denials of this kind of care in California and overturned 51. Across all years since 2001: 35% of 499.

43%“not medically necessary” denials overturned since 202191 decisions
39%“experimental” denials overturned since 202131 decisions
35%overturned across all years since 2001499 decisions

Year by year

2002: 46% of 26 overturned 2003: 11% of 9 overturned 2004: 25% of 12 overturned 2005: 30% of 23 overturned 2006: 36% of 14 overturned 2007: 45% of 11 overturned 2008: 75% of 12 overturned 2009: 36% of 11 overturned 2010: 67% of 9 overturned 2011: 14% of 21 overturned 2012: 38% of 8 overturned 2013: 47% of 17 overturned 2014: 30% of 23 overturned 2015: 21% of 24 overturned 2016: 23% of 35 overturned 2017: 37% of 38 overturned 2018: 28% of 29 overturned 2019: 22% of 23 overturned 2020: 34% of 32 overturned 2021: 36% of 25 overturned 2022: 28% of 39 overturned 2023: 59% of 27 overturned 2024: 45% of 22 overturned 2025: 56% of 9 overturned
2002Share overturned each year · dashed line: 50%2025
Show as a table
YearDecisionsOverturned
20022646%
2003911%
20041225%
20052330%
20061436%
20071145%
20081275%
20091136%
2010967%
20112114%
2012838%
20131747%
20142330%
20152421%
20163523%
20173837%
20182928%
20192322%
20203234%
20212536%
20223928%
20232759%
20242245%
2025956%

By treatment

TreatmentAll yearsSince 2021
General anesthesia26% of 14845% of 33
Hyperbaric oxygen34% of 7328% of 32
Stem cell transplant41% of 566 decisions
Organ transplant50% of 348 decisions

Treatments with at least 20 decisions, most decisions first. Rates on fewer than 20 decisions aren’t shown.

Recent decisions

The most recent decisions in the data, half overturned and half upheld. Each shows the reviewer’s published findings.

  1. Upheld 2025 · Medical necessity · age 11–20 Other · Bones, joints and muscles The physician reviewer found that a patient has requested authorization and coverage for platelet-rich plasma (PRP) injections to the left knee.The records indicate that this patient is being treated for chronic left knee osteoarthritis. The patient is status…

    The physician reviewer found that a patient has requested authorization and coverage for platelet-rich plasma (PRP) injections to the left knee.The records indicate that this patient is being treated for chronic left knee osteoarthritis. The patient is status post left knee arthroscopy with partial medial meniscectomy, shaving, and debridement, left knee diagnostic arthroscopy, and left knee medial meniscus allograft transplantation. The patient presents with chronic left medial knee osteoarthritis and symptoms including locking, giving out, and swelling. The patient’s physical examination of the left knee revealed medial joint line tenderness and trace effusion. X-rays showed no acute fracture or dislocation, with evidence of KL-3 moderate osteoarthritis. The patient has tried and failed treatment with physical therapy and medications. The patient’s provider has recommended treatment with PRP injections. However, limited published, large-scale, long-term peer-reviewed literature suggests that PRP injections for this patient’s knee osteoarthritis are not recommended. Medical literature reports inconsistent and low quality evidence regarding the effectiveness of PRP for knee osteoarthritis, with no clear demonstration of meaningful clinical benefit. Given these findings, the requested PRP injections to the left knee are not medically necessary for the treatment of this patient. Final Result: The reviewer determined that the requested service is not medically necessary for the treatment of the patient's medical condition. Therefore, the Health Plan's denial should be upheld. Credentials/Qualifications: The reviewer is board-certified in orthopedic surgery and is actively practicing. The reviewer is an expert in the treatment of the patient’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-46337

  2. Upheld 2025 · Medical necessity · age 65+ Hyperbaric oxygen · Brain and nerves Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for hyperbaric oxygen therapy. As evidenced by the medical literature, hyperbaric oxygen therapy is a well-established treatment for certain medical conditions, but…

    Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for hyperbaric oxygen therapy. As evidenced by the medical literature, hyperbaric oxygen therapy is a well-established treatment for certain medical conditions, but the management of both chronic venous stasis ulcers and cerebral palsy are not included in the indications list recognized by the Undersea and Hyperbaric Medical Society (UHMS). The UHMS maintains a list of approved conditions for which hyperbaric oxygen therapy has demonstrated clinical efficacy, based on scientific evidence and medical consensus. While hyperbaric oxygen therapy continues to be explored for various potential applications, any condition not listed by UHMS lacks official recognition for its use. Although some practitioners may explore hyperbaric oxygen therapy as an adjunctive approach, its effectiveness remains unproven for the conditions at issue. Though the current evidence is not exhaustive, hyperbaric oxygen therapy is indicated in patients with microvascular injury. It remains relevant to note that problem wounds with delayed healing are primarily designated for diabetic foot ulcers meeting Wagner 3 or greater classification. Overall, there is insufficient support in the medical literature and guidelines for the requested treatment in this patient’s clinical setting. For these reasons, the requested hyperbaric oxygen therapy is not medically necessary for the treatment of this patient. Final Result: The reviewer determined that the requested treatment is not medically necessary for the treatment of the patient's medical condition. Therefore, the Health Plan's denial should be upheld. Credentials/Qualifications: The reviewer is board-certified in internal medicine with subspecialty certification in undersea and hyperbaric medicine and is actively practicing. The reviewer is an expert in the treatment of the enrollee's medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-44606

  3. Overturned 2025 · Medical necessity · age 51–64 General anesthesia · Hormones and metabolism The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for monitored anesthesia care (MAC) to be provided during a colonoscopy. In this case, the patient meets two independent…

    The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for monitored anesthesia care (MAC) to be provided during a colonoscopy. In this case, the patient meets two independent, policy-recognized indications for MAC sedation. The records establish that the patient is obese with a body mass index (BMI) in excess of 35 kg/m2. Further, the patient has experienced a prior reaction to standard sedation during a medical procedure. Overall, MAC is medically appropriate in this clinical setting for the safe administration of anesthesia to the patient. Thus, the requested MAC to be provided during a colonoscopy is medically necessary for the evaluation of the patient. Final Result: The reviewer determined that the service is medically necessary for the evaluation of the patient's medical conditions. Therefore, the Health Plan's denial should be overturned. Credentials/Qualifications: The reviewer is board-certified in anesthesiology and is actively practicing. The reviewer is an expert in the treatment of the enrollee's medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-44555

  4. Overturned 2025 · Medical necessity · age 65+ Other · Immune system The physician reviewer found that a patient has requested authorization and coverage for infusion location at a hospital-based outpatient infusion center for the administration of the previously approved Nulojix intravenous infusion. Nulojix (belatacept) is…

    The physician reviewer found that a patient has requested authorization and coverage for infusion location at a hospital-based outpatient infusion center for the administration of the previously approved Nulojix intravenous infusion. Nulojix (belatacept) is safe to administer in a home setting with no increase in risk. However, an outpatient procedure such as the administration of Nulojix is typically performed in a hospital setting when there are special health concerns. In this case, the records submitted indicate that the patient has special health considerations that require Nulojix infusion in the hospital setting. For these reasons, the requested infusion location at a hospital-based outpatient infusion center for the administration of the previously approved Nulojix intravenous infusion is medically necessary for the treatment of this patient. Final Result: The reviewer determined that the requested service is medically necessary for the treatment of the patient's medical condition. Therefore, the Health Plan's denial should be overturned. Credentials/Qualifications: The reviewer is board-certified in internal medicine with subspecialty certification in nephrology and is actively practicing. The reviewer is an expert in the treatment of the enrollee's medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-44130

  5. Overturned 2025 · Medical necessity · age 51–64 Conscious sedation · Prevention Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for monitored anesthesia care (MAC) provided during a colonoscopy. Findings: The physician reviewer found that MAC during this patient’s colonoscopy was indicated based on…

    Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for monitored anesthesia care (MAC) provided during a colonoscopy. Findings: The physician reviewer found that MAC during this patient’s colonoscopy was indicated based on several factors. A family history of malignant hyperthermia is a significant consideration in anesthetic planning. Malignant hyperthermia is a potentially fatal condition triggered by certain anesthetic agents, such as volatile inhalational agents and succinylcholine. Although MAC with propofol boluses avoids these triggers, the heightened risk associated with this condition requires careful monitoring by an anesthesia provider experienced in malignant hyperthermia to rapidly address any complications. Furthermore, colonoscopies can induce discomfort, pain, and anxiety, requiring sedation for patient tolerance and procedural success. Propofol sedation, administered under MAC, allows titration to an appropriate depth of sedation while maintaining spontaneous ventilation and hemodynamic stability. The presence of an anesthesia professional ensures that the patient is closely monitored for any adverse reactions or complications. Patients undergoing a colonoscopy, even without significant medical history, may experience airway obstruction, hypoventilation, or hemodynamic changes due to sedation. The presence of a skilled anesthesia provider ensures that these risks are mitigated and managed promptly. Adequate sedation also improves procedural efficiency and comfort for the patient, reducing the likelihood of aborted or incomplete procedures due to patient intolerance. Given these findings, the MAC provided during a colonoscopy was medically necessary for the treatment of this patient. Final Result: The reviewer determined that the service at issue was medically necessary for the treatment of the patient’s medical condition. Therefore, the Health Plan’s denial should be overturned. Credentials/Qualifications: The reviewer is board certified in anesthesiology and is actively practicing. The reviewer is an expert in the treatment of the patient’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-43716

  6. Overturned 2025 · Medical necessity · age 21–30 Hyperbaric oxygen · Skin Nature of Statutory Criteria/Case Summary: The patient requested reimbursement for hyperbaric treatments provided on a daily basis, including weekends. In this case, the patient underwent bilateral modified mastectomies with advancement flaps and free nipple…

    Nature of Statutory Criteria/Case Summary: The patient requested reimbursement for hyperbaric treatments provided on a daily basis, including weekends. In this case, the patient underwent bilateral modified mastectomies with advancement flaps and free nipple grafting. The provider postoperatively diagnosed threatened and compromised surgical flaps with ischemic changes threatening the newly grafted tissue. Thus, hyperbaric treatments provided on a daily basis, including weekends were medically necessary for this patient. Final Result: The reviewer determined that the requested services were medically necessary for the treatment of the patient’s medical condition. Therefore, the Health Plan’s denial should be overturned. Credentials/Qualifications: The reviewer is board-certified in internal medicine with a subspecialty certification in undersea and hyperbaric medicine and is actively practicing. The reviewer is an expert in the treatment of the enrollee’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN25-43683

  7. Overturned 2025 · Experimental or investigational · age 41–50 Organ transplant · Cancer The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for a liver transplant. Metastatic carcinoid or neuroendocrine tumor is a rare cancer that is generally not responsive to cytotoxic…

    The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient has requested authorization and coverage for a liver transplant. Metastatic carcinoid or neuroendocrine tumor is a rare cancer that is generally not responsive to cytotoxic chemotherapy. This patient has a metastatic neuroendocrine tumor that is currently restricted to the liver. Since this patient's diagnosis, the patient’s medical care has very closely adhered to National Comprehensive Cancer Network (NCCN) guideline recommendations. However, at this time, the patient has exhausted all standard treatment options and is therefore being considered for transplant. A liver transplant is a reasonable next step for this patient who has tried and failed several standard therapies. There are clinical studies showing significant survival rates for patients undergoing liver transplantation for neuroendocrine liver metastasis. For these reasons, the requested liver transplant is likely to be more beneficial for the treatment of this patient’s condition than any available standard therapy. Findings: Two of the three reviewers found that the requested procedure is likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Final Result: The reviewers determined that the requested procedure is likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Therefore, the Health Plan's denial should be overturned. Credentials/Qualifications: Reviewer 1 is board-certified in medical oncology with subspecialty certification in hematology and is actively practicing. Reviewer 2 is board-certified in internal medicine with subspecialty certifications in hematology and medical oncology and is actively practicing. Reviewer 3 is board-certified in internal medicine with subspecialty certifications in hematology and medical oncology and is actively practicing. The reviewers are experts in the treatment of the patient’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case EI25-45314

  8. Upheld 2025 · Experimental or investigational · age 51–64 Other · Infection Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for laser treatments. In this case, topical antifungals are supported by stronger data and remain a recommended standard of care. In addition, topical antifungals offer a safer…

    Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for laser treatments. In this case, topical antifungals are supported by stronger data and remain a recommended standard of care. In addition, topical antifungals offer a safer and more effective treatment. All told, the laser treatments were not likely to be more beneficial for the treatment of this patient’s condition than any available standard therapy. Findings: Three of the three reviewers found that the services were not likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Final Result: The reviewers determined that the services were not likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Therefore, the Health Plan's denial should be upheld. Credentials/Qualifications: Reviewer 1 is board-certified in podiatry and is actively practicing. Reviewer 2 is board-certified in foot surgery and is actively practicing. Reviewer 3 is board-certified in podiatry and foot and ankle surgery and is actively practicing. The reviewers are experts in the treatment of the enrollee's medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case EI25-44397

  9. Upheld 2025 · Experimental or investigational · age 65+ Other · Skin Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for Sanuwave Ultramist system services. Findings: Various methods, including surgical, mechanical, autolytic, and enzymatic, are recommended for managing chronic ulcers…

    Nature of Statutory Criteria/Case Summary: A patient has requested reimbursement for Sanuwave Ultramist system services. Findings: Various methods, including surgical, mechanical, autolytic, and enzymatic, are recommended for managing chronic ulcers. Low-frequency nonthermal ultrasound would be considered an adjunct therapy after other therapies have failed. In this case, the records do not show that the patient has tried and failed other therapies. Therefore, the Sanuwave Ultramist system services were not likely to have been more beneficial for the treatment of the patient than any available standard therapy. Findings: Two of the three reviewers found that the services at issue were not likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Final Result: The reviewers determined that the services at issue were not likely to be more beneficial for the treatment of the patient's medical condition than any available standard therapy. Therefore, the Health Plan's denial should be upheld. Credentials/Qualifications: Reviewer 1 is board-certified in internal medicine with subspecialty certification in infectious diseases and is actively practicing. Reviewer 2 is board-certified in internal medicine with subspecialty certification in infectious diseases and is actively practicing. Reviewer 3 is board-certified in internal medicine with subspecialty certification in infectious diseases and is actively practicing. The reviewers are experts in the treatment of the enrollee's medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case EI25-43827

  10. Upheld 2024 · Medical necessity · age 51–64 Other · Digestive system Nature of Statutory Criteria/Case Summary: The patient has requested reimbursement for monitored anesthesia care (MAC). MAC is supported in the literature in cases including difficult intubation, airway obstruction, allergies to sedation medications, chronic…

    Nature of Statutory Criteria/Case Summary: The patient has requested reimbursement for monitored anesthesia care (MAC). MAC is supported in the literature in cases including difficult intubation, airway obstruction, allergies to sedation medications, chronic alcohol or illicit drug use resulting in increased tolerance to sedation medications, age over 70, pregnancy, increased aspiration risk, prolonged procedures requiring deep sedation, previously anticipated intolerance to standard sedatives, American Society of Anesthesiologists (ASA) class III or higher, increased risk for airway obstruction due to an anatomic variant, or morbid obesity. According to the most recent guidelines from the American Society for Gastrointestinal Endoscopy (ASGE), consciousness during endoscopic procedures is acceptable and is the goal during most procedures. In this case, the request for monitored anesthesia care is not supported as medically necessary. There is a lack of documentation of the patient having conditions necessitating or supporting the use of MAC in an endoscopic procedure. All told, the MAC was not medically necessary for the evaluation of this patient. Final Result: The reviewer determined that the service at issue was not medically necessary for the treatment of the patient’s medical condition. Therefore, the Health Plan’s denial should be upheld. Credentials/Qualifications: The reviewer is board-certified in internal medicine with subspecialty certification in gastroenterology and is actively practicing. The reviewer is an expert in the treatment of the enrollee’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN24-43354

  11. Upheld 2024 · Medical necessity · age 31–40 Hyperbaric oxygen · Cancer The physician reviewer found that a patient has requested reimbursement and prospective authorization and coverage for hyperbaric oxygen therapy (HBOT) in a medical-grade hyperbaric monoplace chamber. Based on the available records, the flap failure and…

    The physician reviewer found that a patient has requested reimbursement and prospective authorization and coverage for hyperbaric oxygen therapy (HBOT) in a medical-grade hyperbaric monoplace chamber. Based on the available records, the flap failure and necrosis described in this patient’s clinical setting are known possible side effects that providers can manage with various interventions. However, HBOT in a monoplace chamber supervised by a plastic surgeon was not medically necessary to provide superior benefit versus receiving HBOT at another facility where a similar or superior facility treatment protocol could be provided. The patient was started on HBOT several weeks postoperatively, and there was no evidence of acute skin failure demonstrated in the photographs. Skin failure is typically perioperative, and occurs within the first few days to one week after surgery. In addition, the records and photographs do not support ongoing HBOT. One study reported on patients who were referred for HBOT within 24 hours of mastectomy. The authors concluded that “Early identification of ischemia and early initiation of hyperbaric oxygen (HBO2) therapy can mitigate the effects of ischemia and rescue otherwise non-viable breast flap tissue.” Another study conducted a retrospective study that included patients who were initiated on HBOT up to 13 days postoperatively. The authors concluded that “ischemia or necrosis of the nipple-areola complex or mastectomy skin flap remains frequent complications. HBOT has emerged as a possible intervention for threatened flaps.” Overall, the initiation of HBOT several weeks postoperatively and ongoing treatment is not supported in the medical literature. Therefore, the HBOT in a medical-grade hyperbaric monoplace chamber was not and is not medically necessary for the treatment of this patient. Final Result: The reviewer determined that the services at issue were not and are not medically necessary for the treatment of the patient’s medical condition. Therefore, the Health Plan’s denial should be upheld. Credentials/Qualifications: The reviewer is board-certified in family medicine with subspecialty certification in undersea and hyperbaric medicine and is actively practicing. The reviewer is an expert in the treatment of the enrollee’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN24-43188

  12. Overturned 2024 · Medical necessity · age 21–30 General anesthesia · Digestive system The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient with a diagnosis of nausea, early satiety, and unintentional weight loss has requested authorization and coverage for monitored anesthesia care provided during endoscopy…

    The physician reviewer found that Nature of Statutory Criteria/Case Summary: A patient with a diagnosis of nausea, early satiety, and unintentional weight loss has requested authorization and coverage for monitored anesthesia care provided during endoscopy. In this case, the patient reported a history of waking up during procedures with light sedation, resulting in anxiety and an aversion to endoscopic procedures. As such, the patient’s provider has recommended that the patient undergo esophagogastroduodenoscopy with monitored anesthesia care. Overall, the medical literature supports the use of monitored anesthesia care in this patient’s clinical setting. For these reasons, the requested monitored anesthesia care provided during endoscopy is medically necessary for the treatment of this patient. Final Result: The reviewer determined that the requested services are medically necessary for the treatment of the patient’s medical condition. Therefore, the Health Plan’s denial should be overturned. Credentials/Qualifications: The reviewer is board certified in internal medicine with subspecialty certification in gastroenterology and is actively practicing. The reviewer is an expert in the treatment of the enrollee’s medical condition and knowledgeable about the proposed treatment through recent or current actual clinical experience treating those with the same or a similar medical condition.

    Case MN24-43024

What these numbers mean

  • These are decisions by independent doctors in California’s Independent Medical Review, run by the Department of Managed Health Care for the plans it regulates. They show how past denials ended, not the odds for any one case.
  • “Overturned” means the reviewer sided with the patient and the plan had to cover the care. Only denials that reached independent review are counted.
  • Plans in other states, and self-funded employer plans, use other independent reviewers; their results aren’t in this data.

Source: California Department of Managed Health Care, Independent Medical Review (IMR) Determinations, California Health and Human Services Open Data Portal, updated June 1, 2026. 42,749 decisions from 2001 to 2026 (2026 partial).