CPB Medical Billing cheat sheet

CPT codes describe procedures and services; ICD-10-CM codes describe diagnoses. Every claim line needs a supporting diagnosis, and the first-listed diagnosis must reflect the primary reason for the encounter.

E/M level selection under 2021+ office/outpatient rules is based on either medical decision making (MDM) or total time on the date of the encounter; both elements are no longer required together.

Modifier 25 is appended to a significant, separately identifiable E/M service performed on the same day as a procedure; modifier 59 (or XS/XE/XP/XU) signals a distinct procedural service to override bundling edits.

The National Correct Coding Initiative (NCCI) publishes procedure-to-procedure (PTP) edits and medically unlikely edits (MUEs); a PTP edit with a modifier indicator of 0 cannot be bypassed by any modifier.

Global surgical packages include preoperative, intraoperative, and postoperative care. Major surgery (90-day global) and minor surgery (0- or 10-day global) differ in the postoperative period included.

Claim form CMS-1500 is used for professional claims; the UB-04 (CMS-1450) is used for institutional claims. Place of service (POS) codes must match the setting where the service was rendered.

Charges are reported as the practice's fee schedule amount, not the expected reimbursement. Reimbursement is typically the lesser of the billed charge or the payer's allowed amount.

Coordination of benefits (COB) determines which payer is primary. The birthday rule generally makes the plan of the parent whose birthday falls earlier in the year primary for dependent children.

Clean claim rate and first-pass acceptance rate measure front-end billing quality; a claim rejected at the clearinghouse never reaches the payer and does not generate a denial.

Eligibility and benefits verification should confirm active coverage, effective date, plan type, copay/coinsurance, deductible status, and whether prior authorization is required before the date of service.

Prior authorization (PA) must be obtained before the service when the payer requires it; retroactive authorization is generally not guaranteed and services rendered without required PA are commonly denied.

Referral requirements differ by plan: HMO products often require a PCP referral for specialist visits, while PPO products typically do not.

Medicare Part B covers outpatient/professional services and durable medical equipment; Part A covers inpatient hospital stays. Medicare Advantage (Part C) plans follow the plan's own rules but must cover at least the same services as Original Medicare.

Medicaid is a joint federal-state program; eligibility and covered benefits vary by state, and many states use managed care organizations (MCOs) with their own billing rules.

Timely filing limits are set by the payer contract or state regulation; common commercial limits are 90-180 days from the date of service, and Medicare generally is 12 months from the date of service.

Advance Beneficiary Notice (ABN, form CMS-R-131) is used for Medicare when the provider believes a service may not be covered; it shifts financial responsibility to the patient only if properly executed.

For commercial plans, a waiver of patient cost-sharing may violate the payer contract unless the patient is documented as indigent under a written financial assistance policy.

Electronic claims are submitted via ANSI ASC X12N 837P transactions; remittance advice is received as an 835 transaction, and eligibility inquiries use 270/271.

Common denial categories: eligibility (CO-27), no prior authorization (CO-197), non-covered service (CO-96), bundling (CO-97), and medical necessity (CO-50).

CO (contractual obligation) adjustments are written off per contract and cannot be billed to the patient; PR (patient responsibility) amounts may be billed to the patient.

A denial is a payer decision on a processed claim; a rejection is a clearinghouse or front-end edit that prevents the claim from reaching the payer and must be corrected and resubmitted.

Appeal levels for Medicare: first-level redetermination, second-level reconsideration, then ALJ hearing (with amount-in-controversy threshold), Medicare Appeals Council, and federal district court.

Commercial appeals typically require a first-level internal appeal, then external review; the appeal letter should cite the specific denial code, policy reference, and supporting documentation.

Timely filing for appeals is separate from the original claim timely filing limit; Medicare redetermination must generally be filed within 120 days of the initial determination.

Aging buckets (0-30, 31-60, 61-90, 91-120, 120+) track A/R; days in A/R is calculated as total A/R divided by average daily charges.

Patient statements should follow a defined collection cycle with documented notices; accounts are typically turned to a collection agency only after internal collection efforts are exhausted and per written policy.

Refund obligations arise when a payer overpays or a patient pays after insurance has paid; overpayments should be identified and refunded within the timeframe required by the payer contract.

HIPAA Privacy Rule governs use and disclosure of protected health information (PHI); the Security Rule sets administrative, physical, and technical safeguards for electronic PHI.

HIPAA requires covered entities to provide a Notice of Privacy Practices and to honor patient rights including access to records, amendment, and an accounting of disclosures.

The Anti-Kickback Statute prohibits knowingly offering or receiving remuneration to induce referrals of items or services covered by federal health care programs; safe harbors define protected arrangements.

The Stark Law (Physician Self-Referral Law) prohibits physician referrals of designated health services to entities with which the physician has a financial relationship, absent an exception.

The False Claims Act imposes liability for knowingly submitting false claims; qui tam provisions allow private parties to bring suit on the government's behalf.

The OIG Work Plan and the Medicare Learning Network publish audit targets and billing guidance; compliance programs should include auditing, monitoring, and employee training.

CPT is maintained by the AMA; ICD-10-CM is maintained by CDC/NCHS and ICD-10-PCS by CMS; HCPCS Level II codes are maintained by CMS for supplies, drugs, and services not in CPT.

The No Surprises Act limits balance billing for emergency services and out-of-network services at in-network facilities and requires good-faith estimates for uninsured or self-pay patients.

The Two-Midnight Rule governs inpatient admission for Medicare: a stay expected to span two midnights is generally appropriate for inpatient, otherwise outpatient or observation status applies.