Albumin/Creatinine Ratio, Random Urine
Code:7016|CPT:82043, 82570|LOINC:2161-8, 14957-5, 9318-7
| Includes | Creatinine, Urine Albumin, Urine Alb/Creat Ratio |
|---|
Analysis details
Methodology
- Immunoturbidimetry
- Kinetic method
Expected Turnaround Time
1 day
Special Instructions
- Do not consume alcohol for 24 hours before collecting the urine sample.
- Only with clinician approval, hold diuretics for 48 hours prior to urine collection.
How to use
The Albumin/Creatinine Ratio, Random Urine (ACR) is used to identify and track microalbuminuria by quantifying urine albumin and expressing it relative to creatinine in a random specimen. This assay supports early diagnosis and longitudinal follow-up of diabetic nephropathy and is commonly referred to as a microalbumin test or urine microalbumin measurement. It also informs the assessment of kidney involvement related to chronic hypertension, congestive heart failure, glomerulonephritis, and inflammatory or cystic renal diseases. In addition, the ACR assists in evaluating renal involvement in systemic disorders such as systemic lupus erythematosus and amyloidosis, and in investigating suspected nephropathy during pregnancy when routine proteinuria is not present.
Limitations
Microalbuminuria represents urinary albumin excretion that exceeds physiologic levels yet remains below the threshold of overt proteinuria, and it precedes clinical proteinuria. It reflects early glomerular injury and can be reversible with appropriate therapy. Because albumin excretion varies from day to day, confirmation requires a series of measurements. At least two of three measurements over three to six months should be abnormal before concluding that the threshold for microalbuminuria has been met.
| Unit | ratio | ||||
|---|---|---|---|---|---|
| Reference interval |
| ||||
| Indications | Type 2 diabetes mellitus at diagnosis, with repeat testing every 6 months, Type 1 diabetes mellitus of more than 5 years' duration, every 6 months, Pediatric type 1 diabetes mellitus with labile control, beginning 1 year after onset, Chronic or poorly controlled arterial hypertension, Congestive heart failure accompanied by edema, Pregnancy when nephropathy is suspected despite absence of routine proteinuria, Differential evaluation of early-stage glomerulonephritis, Systemic lupus erythematosus or amyloidosis to identify early renal involvement |
Possible Causes of Abnormal Results
Increased levels
- congestive heart failure
- dehydration
- exercise
- fever
- high-protein diet
- infection
- marked hyperglycemia
- marked hypertension
- urinary tract infection
Decreased levels
- ace inhibitors
- excessive hydration
- low-protein diet
- nsaids
Specimen Requirements
| Specimen | Urine |
|---|---|
| Container | Sterile Urine Cup |
| Volume | 10 mL (min 2 mL) |
| Storage Instructions | Room temperature, Refrigerated, Frozen |
References
Metcalf P, Baker J, Scott A, Wild C, Scragg R, Dryson E. Albuminuria in people at least 40 years old: effect of obesity, hypertension, and hyperlipidemia. Clin Chem. 1992 Sep;38(9):1802-1808. PubMed 1526018.
Keane WF, Eknoyan G. Proteinuria, albuminuria, risk, assessment, detection, elimination (PARADE): a position paper of the National Kidney Foundation. Amer. J. Kidney Dis. 2000;33:1004-1010.
Mogensen CE, Keane WF, Bennett PH, et al. Prevention of diabetic renal disease with special reference to microalbuminuria. Lancet. 2005;346:1080-1084.
Saudi J Kidney Dis Transpl. 2012 Mar;23(2):311-315. Ambulatory blood pressure monitoring in children and adolescents with type-1 diabetes mellitus and its relation to diabetic control and microalbuminuria. Basiratnia M, Abadi SF, Amirhakimi GH, Karamizadeh Z, Karamifar H.