BASE FFS Claims Files

Providers submit the below claim types to CMS in order to be reimbursed for serviced provided to fee-for-service (FFS) beneficiaries. Brief summaries are provided below for each Medicare BASE (i.e., files obtained directly from CMS) FFS claim file included in SEER-Medicare. Additional links with more details are provided below to CMS’s Research Data Assistance Center (ResDAC) and Chronic Conditions Warehouse (CCW) websites. Investigators should note that given SEER-Medicare privacy policies, some variables, namely identifiers of persons and providers and geographical locations such as zip codes, have been encrypted.

For Medicare beneficiaries with FFS coverage, claims data are available for two cohorts: persons with and without cancer (see Summary Table of Available Data for more specifics). Beginning October 1, 2015, the coding system for diagnosis codes and procedure codes switched from ICD-9 to ICD-10.

The Medicare claims files provided as part of SEER-Medicare are described below and reflect input from staff at NCI and CMS.

Medicare Provider Analysis and Review (MedPAR)

The MedPAR file includes all Part A short stay, long stay, and skilled nursing facility (SNF) bills for each calendar year. MedPAR contains one summarized record per admission. Each record includes up to 25 diagnoses (ICD9/ICD10) and 25 procedures ((ICD9/ICD10) provided during the hospitalization.

Researchers interested in only short-stay hospitalizations will need to subset the MedPAR file using the variable 'MedPAR short stay/long stay/skilled nursing facility (SNF) indicator code' located in column 106 ('S' = short stay, 'L' = long stay and 'N' = skilled nursing stay).

In almost all cases, a single MedPAR record reflects a summary of all care provided during an institutional stay. However, if the stay is long, there may be more than one claim per stay. This occurs most frequently for stays in SNFs as these often span several months. SNFs records often have no discharge date as persons remain in institutions beyond the period of Medicare coverage.

Several fields on the MedPAR file are not considered reliable:

• source of admission;
• discharge destination; and
• group health organization payment code.

View ResDAC’s MedPAR File Overview

View CCW’s MedPAR Record Layout and Data Dictionary

Carrier Claims (NCH)

Since 1991, the Center for Medicare & Medicaid Services (CMS) has collected physician/supplier (Part B) bills for 100 percent of all claims. These bills, known as the National Claims History (NCH) records, are largely from physicians although the file also includes claims from other non-institutional providers such as physician assistants, clinical social workers, nurse practitioners, independent clinical laboratories, ambulance providers, and stand-alone ambulatory surgical centers. The claims are processed by carriers working under contract to CMS. Each carrier claim must include a Health Care Procedure Classification Code (HCPCS) to describe the nature of the billed service. The HCPCS is composed primarily of CPT-4 codes developed by the American Medical Association, with additional codes specific to CMS. Each HCPCS code on the carrier bill must be accompanied by a diagnosis code (ICD9, ICD10), providing a reason for the service. In addition, each bill has the fields for the dates of service, reimbursement amount, encrypted provider numbers (e.g., UPIN, NPI), and beneficiary demographic data.

Carrier Claims Details:

• Carrier claims are non-institutional claims, however this does not mean that they are outpatient claims. Providers, such as physicians, can bill for services provided in the office, hospital, or other sites. To identify where the service is provided, one needs to assess the variable "line place of service", which specifies the place of service.
• There are three subfiles – base file, line file and demonstrations/innovations code file. The base file contains the overall claim level information (e.g., claim ID, beneficiary ID, claim type, referring physician, claim from date, claim through date, claim processing date, carrier number, claim payment amount, claim allowed charge amount, and diagnosis codes). The line file contains the individual line level information from the claims (e.g., the procedure codes with the diagnosis associated with the procedure, first and last expense dates, line allowed charge amount, line submitted charge amount, and performing provider identifier).
• There are two pairs of date fields. The fields "claim from" and "claim through" dates cover a period of service (usually but not always a single date of service), while the "line first expense date" and "line last expense date" reflect the specific day of service.
• For every billed procedure (using a HCPCS code), there should be a corresponding ICD-9 or ICD-10 diagnosis code (often called the line item diagnosis) that provides the reason for the billed service. In the case of lab tests, the diagnosis will often be XXOOO because the outside lab has no information from the physician about the reason for the test. In addition, the carrier claim contains space for 12 diagnoses, these are listed on the base file and are often referred to as the “header” diagnoses. These are not necessarily linked with any of the procedures on the claim but may reflect co-existing health conditions. The accuracy of the diagnoses on the carrier data has not been determined.
• Selected services may not appear in the carrier claims, even if they have been provided. For example, CMS pays physicians a fixed amount for surgeries, a payment practice known as bundling. As part of bundling, CMS expects that certain care will be included in the payment amount, such as the first one or two office visits following surgery or a biopsy just before surgery. Bundled services will not appear in the physician data. Interpretation of the rules on bundling varies by carrier.

View ResDAC’s Carrier (Fee-For-Service) File Overview

View CCW’s Medicare Claims Record Layout and Codebook

Outpatient Claims

The outpatient file contains Part B claims for 100 percent for each calendar year from institutional outpatient providers. Examples of institutional outpatient providers include hospital outpatient departments, rural health clinics, renal dialysis facilities, outpatient rehabilitation facilities, comprehensive outpatient rehabilitation facilities, community mental health centers. In and out surgeries performed in a hospital will be in the hospital outpatient file, while bills for surgeries performed in freestanding surgical centers appear in the carrier claims, not in the outpatient file.

There are multiple parts to this file: base file, revenue center file, condition code file, occurrence code file, span code file, value code file, and demonstration/innovation code file.

Some of the information contained in this outpatient file includes diagnosis and procedure codes, dates of service, reimbursement amounts, facility provider number, revenue center codes and beneficiary demographic information. Although the outpatient file contains data fields for ICD-9 or ICD-10 procedure codes, the reporting of these codes has been sporadic since 2000 when CPT/HCPCS codes replaced ICD-9 procedure codes as the basis of billing the Centers for Medicare & Medicaid Services for outpatient procedures. Since 2004, services from the outpatient bill have been captured from CPT/HCPCS codes and from the revenue centers.

As with the carrier data, there may be multiple records for the same date of service. Additionally, data related to each revenue center on a claim are written to a separate record.

View ResDAC’s Outpatient File Overview

View CCW’s Medicare Claims Record Layout and Codebook

Home Health Agency (HHA)

The Home Health Agency file contains 100 percent of all claims for home health services. Some of the information contained in this file includes the number of visits, type of visit (skilled-nursing care, home health aides, physical therapy, speech therapy, occupational therapy, and medical social services), diagnosis (ICD-9 or ICD10 diagnosis), the dates of visits, reimbursement amount, HHA provider number, and beneficiary demographic information. An HHA bill may cover services provided over a period of time, not a single day.

There are multiple parts to this file: base file, revenue center file, condition code file, occurrence code file, span code file, value code file, and demonstration/innovation code file.

View ResDAC’s HHA File Overview

View CCW’s Medicare Claims Record Layout and Codebook

Durable Medical Equipment (DME)

The Durable Medical Equipment (DME) contains final action claims data submitted to Durable Medical Equipment Regional Carriers (DMERCs). Some of the information contained in this file includes diagnosis, (ICD-9 or ICD-10 diagnosis), services provided (HCFA Common Procedure Coding System (HCPCS) codes), dates of service, reimbursement amount, DME provider number, and beneficiary demographic information. Claims for DME services that are processed by a carrier will be found in the NCH file. Claims for DME services that are processed by DMERCs will be found in the DME file. For example, claims for oral equivalents of IV chemotherapies will be found in the DME file.

There are multiple parts to this file: base file, line file, and demonstration/innovation code file.

View ResDAC's DME File overview

View CCW’s Medicare Claims Record Layout and Codebook.