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ModifiedCurativePolicy CHP-IP-2026-060

Acute Appendicitis — Inpatient and Level-of-Care Management

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This policy governs acute inpatient admission, observation, outpatient management, ICU and intermediate-care placement, continued stay, and discharge readiness for Curative commercial members with suspected or confirmed acute appendicitis. Elective interval appendectomy is outside scope.

Policy Summary

PayerCurative

PolicyAcute Appendicitis — Inpatient and Level-of-Care Management

Policy CodePolicy CHP-IP-2026-060

Change TypeModified

Effective DateN/A

Next Review DateN/A

Key ActionDocument the antibiotic regimen, start date, planned stop date, and daily progress notes addressing continued-stay criteria.

SourceLink

POLICY UPDATE CHANGES

Postoperative antibiotic therapy for complicated appendicitis was revised from a prior 4-to-7-day course to a short course of approximately 2-to-3 days after adequate source control.

2-3 daysPostoperative antibiotic course after source control

2-5 daysComplicated appendicitis expected stay

0-1 dayUncomplicated laparoscopic appendectomy expected stay

24 hoursConcurrent review interval

65+Age threshold with comorbidity risk factor

Appendicitis Admission and Level-of-Care Criteria

Initial inpatient admission

Acute inpatient admission is medically necessary when ALL of the following are met.

Inpatient admission

Clinical severity finding
- Complicated appendicitis on CT, ultrasound, or MRI, including perforation, extraluminal air, abscess, phlegmon, or gangrene.
- Generalized peritonitis: Diffuse rigidity or rebound beyond the right lower quadrant.
- Sepsis with intra-abdominal source: Sepsis with qSOFA 2 or more, lactate above 2 mmol/L, or systolic blood pressure below 90 mmHg.qSOFA >=2; lactate >2 mmol/L; or SBP <90 mmHg

Policy Summary

PayerCurative

PolicyAcute Appendicitis — Inpatient and Level-of-Care Management

Policy CodePolicy CHP-IP-2026-060

Change TypeModified

Effective DateN/A

Next Review DateN/A

Key ActionDocument the antibiotic regimen, start date, planned stop date, and daily progress notes addressing continued-stay criteria.

SourceLink

On This Page

High-risk uncomplicated appendicitis: Uncomplicated appendicitis with ASA III or higher, immunosuppression, pregnancy, anticoagulation requiring reversal, or age 65 or older with comorbidity.ASA >=III or age >=65 with comorbidity

Intake or kidney impairment: Inability to tolerate oral intake or acute kidney injury from dehydration with creatinine at least 1.5 times baseline.Creatinine >=1.5 times baseline

Hospital-level service

Postoperative monitoring: Appendectomy with expected postoperative monitoring beyond 24 hours because of complicated disease, peritoneal contamination, or comorbidity.>24 hours expected monitoring
Abscess drainage: Image-guided percutaneous abscess drainage with IV antibiotics.
IV antibiotics for complicated appendicitis or nonoperative management when oral therapy cannot be taken.
Sepsis resuscitation: IV fluid resuscitation and frequent reassessment for sepsis.

Observation or outpatient instead of inpatient

Outpatient surgery, observation generally up to 24 to 48 hours, or outpatient management is appropriate when ANY of the following applies and no inpatient admission criterion is met.

Observation or outpatient management

Uncomplicated appendectomy: Uncomplicated appendicitis treated by laparoscopic appendectomy with expected same-day or next-day discharge.
Equivocal diagnosis: Intermediate Alvarado score of 5 to 6 or AIR score of 5 to 8 requiring serial examination or imaging over up to 24 hours.Alvarado 5-6 or AIR 5-8
Selected nonoperative treatment: Uncomplicated appendicitis without appendicolith managed with oral antibiotics in a member who tolerates oral intake and has reliable follow-up.No appendicolith; tolerates oral intake; reliable follow-up
Low-probability presentation: Alvarado score 4 or lower or AIR score 4 or lower, suitable for discharge with return precautions.Alvarado <=4 or AIR <=4

Intensive care unit

ICU care is appropriate when ANY of the following is present.

ICU level of care

Septic shock requiring vasopressors to keep mean arterial pressure at 65 mmHg or more, or lactate above 4 mmol/L.MAP >=65 mmHg with vasopressors or lactate >4 mmol/L
Respiratory failure requiring mechanical ventilation or high-flow oxygen.
Abdominal compartment or open abdomen: Abdominal compartment syndrome or need for open abdomen management.

Step-down or intermediate care

Step-down or intermediate care is appropriate when ANY of the following is present.

Intermediate care

Sepsis without vasopressors: Sepsis with lactate 2 to 4 mmol/L or fluid-responsive hypotension, without need for vasopressors.Lactate 2-4 mmol/L or fluid-responsive hypotension
Cardiopulmonary monitoring: Significant cardiopulmonary comorbidity requiring telemetry or frequent vital signs after surgery.

Medical-surgical unit

A medical-surgical unit is appropriate when ANY of the following is present.

Medical-surgical level

Complicated appendicitis after procedure: After appendectomy or drainage for complicated appendicitis while receiving IV antibiotics.
Nonoperative IV therapy: Nonoperative management requiring IV antibiotics and serial examination.
Postoperative ileus requiring IV fluids or nasogastric decompression.

Discharge readiness

Discharge is appropriate when ALL of the following are met.

Vital-sign stability: For complicated disease, temperature is below 38.0 C for at least 24 hours, and heart rate is below 100/min.Temperature <38.0 C for >=24 hours; heart rate <100/min
Oral intake and pain control: The member tolerates oral diet and oral medications, and pain is controlled with oral analgesics.
Improving laboratory and wound status: WBC is normalizing or decreasing, with no clinical sign of abscess or wound infection.
Antibiotic plan: No antibiotics are planned after appendectomy for uncomplicated disease; after source control for complicated disease, the total postoperative course is limited to the short course supported by guidelines.Short course after source control
Drain and surgical follow-up: A drain-care plan is documented when a drain is present, with surgical follow-up within 1 to 2 weeks.Follow-up within 1-2 weeks
Nonoperative or abscess follow-up: For nonoperative management or drained abscess, follow-up includes interval imaging or colonoscopy when indicated to exclude neoplasm, especially at age 40 or older.Especially age >=40

Continued-stay criteria

Continued stay is medically necessary when ANY of the following is documented and is reviewed every 24 hours.

Continued stay

Ongoing sepsis or fever: Ongoing sepsis physiology or temperature 38.0 C or higher within the prior 24 hours.Temperature >=38.0 C in prior 24 hours
Ileus or oral intolerance: Ileus or inability to tolerate oral intake requiring IV fluids.
Undrained abscess or active drainage: Undrained intra-abdominal abscess, drain output requiring inpatient management, or planned drainage procedure.
IV-to-oral antibiotic conversion not possible: IV antibiotics cannot be converted to oral therapy because of intolerance or resistant organisms.
Wound infection with systemic signs: Wound infection requiring opening and packing with systemic signs.

Elective interval appendectomy is outside the scope of this policy. The policy applies to acute appendicitis management, including inpatient admission, observation, level of care, continued stay, and discharge readiness.

Inpatient admission for uncomplicated laparoscopic appendectomy in an otherwise healthy member with an expected discharge within 24 hours does not meet medical-necessity criteria. Outpatient surgery or observation is the appropriate level of care when no inpatient criterion is present.

Continued IV antibiotics beyond the guideline-supported short course after adequate source control in a clinically improving member does not meet criteria. Continued stay solely for this reason is referred for physician review.

A continued stay after discharge-readiness criteria are met while awaiting transportation, home services, or follow-up imaging is considered a convenience day and does not meet medical-necessity criteria. The case should be routed for physician review and discharge planning rather than treated as an automated denial.

Postoperative antibiotics after appendectomy for uncomplicated appendicitis are not medically necessary because postoperative antibiotics are not recommended for uncomplicated disease.

Applicable Diagnosis, Procedure, and Utilization Coding

ICD-10-CM: acute appendicitis with generalized peritonitisICD-10

K35.200	Acute appendicitis with generalized peritonitis
K35.201	Acute appendicitis with generalized peritonitis
K35.209	Acute appendicitis with generalized peritonitis
K35.210	Acute appendicitis with generalized peritonitis
K35.211	Acute appendicitis with generalized peritonitis
K35.219	Acute appendicitis with generalized peritonitis

ICD-10-CM: acute appendicitis with localized peritonitisICD-10

K35.30	Acute appendicitis with localized peritonitis
K35.31	Acute appendicitis with localized peritonitis
K35.32	Acute appendicitis with localized peritonitis
K35.33	Acute appendicitis with localized peritonitis

ICD-10-CM: other and unspecified acute appendicitisICD-10

K35.80	Other and unspecified acute appendicitis
K35.890	Other and unspecified acute appendicitis
K35.891	Other and unspecified acute appendicitis

ICD-10-PCS: appendectomy and percutaneous drainageICD-10

0DTJ4ZZ	Appendectomy and percutaneous drainage
0DTJ4ZG	Appendectomy and percutaneous drainage
0DTJ0ZZ	Appendectomy and percutaneous drainage
0W9G30Z	Appendectomy and percutaneous drainage
0W9G3ZZ	Appendectomy and percutaneous drainage

CPT: appendectomy and image-guided drainageCPT

44950	Appendectomy and image-guided drainage
44960	Appendectomy and image-guided drainage
44970	Appendectomy and image-guided drainage
49406	Appendectomy and image-guided drainage

MS-DRGRevenue

397	MS-DRG
398	MS-DRG
399	MS-DRG
371	MS-DRG
372	MS-DRG
373	MS-DRG

Revenue codesRevenue

0120	Revenue code
0250	Revenue code
0270	Revenue code
0300	Revenue code
0360	Revenue code
0710	Revenue code

Intermediate Alvarado score

Intermediate Alvarado range5 to 6

Clinical useIndicates an equivocal diagnosis requiring serial examination or imaging

Typical settingObservation or outpatient management, generally for up to 24 hours when no inpatient criterion is met

Intermediate AIR score

Intermediate AIR range5 to 8

Clinical useIndicates an equivocal diagnosis requiring serial examination or imaging

Typical settingObservation or outpatient management, generally for up to 24 hours when no inpatient criterion is met

Low-probability Alvarado score

Low-probability Alvarado threshold4 or lower

Clinical useSupports a low-probability presentation

Typical dispositionDischarge with return precautions when no inpatient criterion is met

Low-probability AIR score

Low-probability AIR threshold4 or lower

Clinical useSupports a low-probability presentation

Typical dispositionDischarge with return precautions when no inpatient criterion is met

Sepsis hypotension threshold

Systolic blood pressure thresholdBelow 90 mmHg

Associated conditionSepsis with an intra-abdominal source

Inpatient relevanceMay satisfy a clinical severity finding when accompanied by the required hospital-level service

ICU septic shock threshold

Vasopressor criterionVasopressors required to keep mean arterial pressure at 65 mmHg or more

Lactate criterionLactate above 4 mmol/L

Level of careEither criterion supports ICU care when present

Review, Documentation, and Determination Requirements

Note

Clinical Review and Physician Determination

Evaluate acute inpatient, observation, level-of-care, continued-stay, and discharge-related requests against the applicable criteria and generally accepted standards of medical practice. Automated systems and non-physician reviewers may approve requests in full or in part, but may not issue an adverse determination; requests that do not meet criteria must be referred to a licensed physician of the same or similar specialty.

Apply concurrent review to each continued-stay period.
Do not treat the absence of a specifically addressed service as a basis for adverse determination.
Previously authorized days are not retroactively denied; expected length of stay is a planning benchmark, not a limit on covered days.
The Medicare two-midnight benchmark is not a coverage criterion for these commercial plans, and CMS inpatient-only status is not required for approval.

Billing Rule

Approve the Supported Portion

When the requested quantity, units, or duration exceed what the documentation supports, approve the supported portion and refer only the unsupported increment for review.

Do not deny the entire request solely because part of it exceeds documented support.

Prior Authorization

Physician Review Required

If a request does not meet criteria, refer it for physician review rather than issuing an adverse determination through an automated system or non-physician review.

Offer the requesting provider a peer-to-peer discussion before an adverse determination.
The reviewing physician must be licensed in the same or similar specialty and meet applicable plan medical-director, licensure, and situs-state requirements.

Documentation Required

Diagnostic and Severity Documentation

Submit the clinical history and examination, Alvarado or AIR score, vital signs, WBC, CRP or lactate when obtained, and sepsis screening. Include imaging classification as complicated or uncomplicated and appendicolith status.

Document scoring and diagnostic findings supporting the requested level of care.
Include findings relevant to sepsis or other severity escalation.

Documentation Required

Procedure and Source-Control Record

Document the operative or procedure findings and the source control achieved, including relevant drainage or other source-control details.

Include the procedure note in the request and medical record.
Identify unresolved collections or other findings that may affect continued stay.

Documentation Required

Antibiotic and Concurrent-Review Documentation

Document the antibiotic regimen, start date, and planned stop date, along with daily progress notes addressing the continued-stay criteria.

Explain why IV therapy cannot be converted to oral therapy when continued inpatient treatment is requested.
Support each continued-stay period with current clinical findings.

Documentation Required

Discharge and Follow-up Documentation

Document the discharge plan, disposition, follow-up, pathology result review, drain care, and any indicated imaging or colon evaluation.

Identify the responsible follow-up clinicians and timing.
Document patient and caregiver instructions for drains and unresolved care needs.

Billing Rule

Support the Requested Quantity and Duration

The full requested quantity, units, and duration must be supported by the clinical documentation and applicable criteria.

Provide documentation for each requested service increment and each continued-stay period.
If only part is supported, approve the supported portion and refer the excess for physician review.

Denial Risk

Uncomplicated Disease Usually Requires a Short Stay

In the described short-stay scenario—a healthy member undergoing laparoscopic appendectomy for uncomplicated disease with expected discharge within 24 hours—inpatient admission is not supported; outpatient surgery or observation is the appropriate level of care.

Inpatient status may be supported when complicated disease, sepsis, or significant comorbidity is documented.

Denial Risk

Antibiotics Beyond the Supported Short Course

Continued inpatient stay solely for IV antibiotics beyond the guideline-supported short course after adequate source control in a clinically improving member is not supported.

Short postoperative courses are generally appropriate after source control; continued stay for antibiotics alone must be referred for physician review.
Document intolerance or resistant organisms when IV antibiotics cannot be converted to oral therapy.

Denial Risk

Postoperative Antibiotics for Uncomplicated Disease

Admission for postoperative antibiotics after appendectomy for uncomplicated appendicitis is not medically necessary.

Postoperative antibiotics are not recommended for uncomplicated disease absent another documented indication.

Denial Risk

Discharge Once Ready

A continued stay after discharge readiness while awaiting transportation, home services, or follow-up imaging is convenience care and is not supported as a medical-necessity reason for continued hospitalization.

Route the case to physician review and discharge planning.
Do not retroactively deny days that were already authorized.

Denial Risk

Clinical Deterioration or Unresolved Complication

Identify and escalate clinical deterioration or an unresolved complication, including worsening pain, peritonitis, persistent fever, sepsis physiology, organ dysfunction, postoperative fever or rising WBC, suspected abscess, ileus or obstruction, or other findings that make discharge unsafe.

Hypotension, lactate above 4 mmol/L, or new organ dysfunction requires sepsis-bundle care, ICU evaluation, and urgent source control.
Worsening symptoms during nonoperative management require repeat imaging and surgical reassessment within 24 hours.
Fever or rising WBC after postoperative day 3 to 5 requires CT evaluation for abscess; drain an abscess if found.
Abdominal distension, vomiting, or no flatus beyond 72 hours requires evaluation for ileus or obstruction, with imaging and decompression as indicated.
Continued stay may be supported for temperature 38.0 C or higher within the prior 24 hours, inability to tolerate oral intake requiring IV fluids, an undrained abscess or inpatient drain management, non-convertible IV antibiotics, or wound infection with systemic signs.

Prior Authorization

Adverse Determinations Require Physician Review

Only a licensed physician of the same or similar specialty may issue an adverse determination, and only after the requesting provider is offered a peer-to-peer discussion.

The physician reviewer must satisfy applicable licensure, specialty, medical-director, and situs-state requirements.
Automated systems and non-physician reviewers may approve in full or in part but may not issue an adverse determination.

Billing Rule

Review Only the Unsupported Excess

When services are partially supported, approve the supported services and refer only the unsupported quantity, units, or duration for physician review.

Do not convert an unsupported excess into an automatic denial of the entire request.
Apply this rule to requested services and to each continued-stay period.

Clinical Background

Acute appendicitis is a common abdominal surgical emergency. Laparoscopic appendectomy is the standard surgical approach, while selected members with uncomplicated appendicitis may be managed with antibiotics alone. Uncomplicated laparoscopic appendectomy is often suitable for same-day or next-day discharge, whereas complicated appendicitis generally requires source control and inpatient IV antibiotics. Clinical risk scores and selective imaging support diagnostic stratification and level-of-care decisions.

Policy Definitions and Utilization Benchmarks

Uncomplicated appendicitis

Core definitionAcute appendicitis without perforation, gangrene, abscess, phlegmon, or generalized peritonitis

Assessment basisClassification is based on imaging or operative findings

Examples of absent complicationsNo perforation, gangrene, abscess, phlegmon, or generalized peritonitis

Complicated appendicitis

Core definitionAppendicitis with perforation, gangrene, periappendiceal abscess or phlegmon, or diffuse peritonitis

Perforation or tissue injuryPerforation or gangrene qualifies as complicated disease

Infectious complicationsPeriappendiceal abscess, phlegmon, or diffuse peritonitis qualifies as complicated disease

Adequate source control

Appendix treatmentRemoval of the appendix

Alternative treatmentPercutaneous drainage of an abscess

Required resultThe intervention controls ongoing contamination

Expected length of stay

PurposePlanning benchmark for an uncomplicated course

Coverage effectNot a limit on covered days

Review implicationCovered duration continues to depend on documented medical necessity and continued-stay criteria

Medicare two-midnight benchmark

PurposePlanning benchmark used in Medicare inpatient payment and utilization contexts

Commercial coverageNot a coverage criterion for these commercial plans

Policy applicationCommercial inpatient status is evaluated under the policy criteria rather than the two-midnight benchmark

Concurrent review

Review timingApplies to each continued-stay period

Previously authorized daysAre not retroactively denied

Expected length of stayIs a planning benchmark, not a limit on covered days