In general, more serum creatinine lab tests were ordered (had the CPT code recorded) then had valid results available in the data. After increasing from 60% in 2005 to 76% in 2008, the notation of CPT codes for serum creatinine testing has been steady at 77%. Availability of results has varied across years between 65-75% of VA patients.
Chart Explanation: A majority of patients in the VA had CPT codes for a serum creatinine test. There was a steady increase in the number of serum creatinine tests ordered by year.
The Veteran’s Affairs (VA) data presented are from a national sample of health care visits to the VA Health System by eligible U. S. veterans. During any given year, ~ 70% of the outpatient population receives a serum creatinine test. While the demographics of VA Health System users are distinct from the general U.S. population, the VA data allow a ‘snapshot’ of clinical practices across the nation.
National VA data were examined for veterans with at least one outpatient visit during the federal fiscal year. To estimate prevalence of CKD, outpatient serum creatinine laboratory results (averaged if a patient had more than one test during the fiscal year) were used to calculate an estimated glomerular filtration rate (eGFR) for each patient using the CKD-EPI equation, excluding dialysis and transplant patients. Estimated GFR (kidney function) was classified into five CKD categories (eGFR =90, eGFR 60-89, stage 3=eGFR 30-59, stage 4=eGFR 15 to 29, and stage 5 without dialysis=eGFR<15 ml/min/1.73 m² and “eGFR Unmeasured” for those patients without serum creatinine testing. Inpatient serum creatinine data were not used as they would be affected by the presence of acute illnesses. Due to the infrequency of testing, albuminuria was not included in the definition of CKD. Dialysis patients were defined by clinic stop-codes (602-611), outpatient procedure codes for dialysis (CPT4: 90921 and 90925), outpatient diagnosis codes (ICD-9-CM: 585.6, V56, V45.1 and E87.91) and inpatient and outpatient diagnosis codes (ICD-9-CM: 5856) to indicate dialysis. Kidney transplant patients were identified by inpatient and outpatient ICD-9-CM diagnosis code V420 and inpatient procedure and surgery codes (55.69).
Testing for serum creatinine can be performed as part of a routine laboratory panel or as an isolated test. CPT procedure codes (80053, 80048, 80050, 80069 and 82565) were used to identify an isolated, specifically-ordered serum creatinine test. The numerator includes the number of patients with evidence of a serum creatinine test procedure code. The denominator was defined as all patients aged 20 years or older in the sample who had at least one outpatient visit during the fiscal year.
This material is the result of work supported with resources and the use of facilities at the Veterans Affairs Ann Arbor Health Care System, Ann Arbor, Michigan.
| Field | Data |
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| Description of Measure | Serum Creatinine laboratory testing practices |
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| Data Source | VA |
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| Type of Data Source | Administrative Data |
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| Data Set | VA National Data, using the MedSAS data files |
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| Health Care System Data | Yes |
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| Regional or National? | National |
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| Demographic Group | Patients in VA health system |
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| Numerator | Participants in denominator with creatinine testing recorded in the medical record with a CPT code. |
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| Denominator | Patients aged >20 who have at least one outpatient visit |
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| Primary Data Source Indicator | Serum Creatinine Test (1 or more during year) |
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| Primary Indicator Method of Measurement | Laboratory |
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| Frequency of Measurement (Primary) | Multiple measurements per patient |
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| Period Currently Available | 2005 - 2018 |
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| Limitations of Indicator | The VA health care system is a closed system – most laboratory requests are processed internally, and payment is generally not dependent upon the presence of a CPT code. Hence procedural codes and serum creatinine lab results do not always correlate. |
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