|
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Albumin/Creatinine Ratio, Timed Urine
Test Code92739
Preferred Specimen
Urine collected in Sterile Cup
Minimum Volume
2 mL
Instructions
Specify total volume and duration of collection on container and test requisition
Transport Container
Plastic urine container
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Refrigerated: 7 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Acid preserved urine
Methodology
Turbidimetric
Reference Range
| Creatinine, Timed Urine | Not established |
| Albumin, Urine | Not established |
| Albumin, Excretion Rate | <20 mcg/min |
| Albumin/Creatinine Ratio | <30 mcg/mg creat |
The ADA defines abnormalities in albumin excretion as follows:
| Category | Result (mcg/min) |
| Normal | <20 |
| Microalbuminuria | 20-199 |
| Clinical albuminuria | ≥200 |
The ADA recommends that at least two of three specimens collected within a 3-6 month period be abnormal before considering a patient to be within a diagnostic category.
Clinical Significance
This test measures the amount of albumin, a large protein, in urine. The presence of albumin in urine may be useful as an early marker of kidney damage. Because the kidneys usually excrete only small molecules into urine, even low levels of albumin in urine (microalbuminuria) may suggest kidney injury [1].
According to the Centers for Disease Control and Prevention (CDC), diabetes and high blood pressure are the major causes of chronic kidney disease (CKD). The CDC recommends regular testing for CKD in people who have diabetes, high blood pressure, and/or other risk factors, such as heart disease, family history of CKD, obesity, previous damage to the kidneys, and older age. The albumin/creatinine ratio is an important part of this assessment [2,3].
Microalbuminuria is a known risk factor for progressive kidney disease and cardiovascular death [4]. The National Kidney Foundation (NKF) recommends annual testing for microalbumin/albumin in all individuals with diabetes whose kidneys are functioning. According to the NKF, annual testing should start 5 years after diagnosis for individuals with type 1 diabetes and at diagnosis for individuals with type 2 diabetes [5].
The NKF recommends that at least 2 of 3 specimens, drawn within a 3- to 6-month period, be reported as abnormal before making a clinical diagnosis of either microalbuminuria or albuminuria [5]. Results are reported as a ratio of albumin (µg) to creatinine (mg).
Test results should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Burtis C, et al. Amino acids and proteins. In: Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 7th ed. St Louis, MO: Elsevier; 2015:314-315.
2. Gaitonde DY, et al. Am Fam Physician. 2017;96:776-783.
3. Centers for Disease Control and Prevention. Chronic kidney disease in the United States, 2019. https://www.cdc.gov/kidneydisease/publications-resources/2019-national-facts.html. Last reviewed March 11, 2019. Accessed February 4, 2020.
4. Weir, MR. Clin J Am Soc Nephrol. 2007;2:581-590.
5. National Kidney Foundation. Am J Kidney Dis. 2007(Suppl 2);49:S1-S180.
According to the Centers for Disease Control and Prevention (CDC), diabetes and high blood pressure are the major causes of chronic kidney disease (CKD). The CDC recommends regular testing for CKD in people who have diabetes, high blood pressure, and/or other risk factors, such as heart disease, family history of CKD, obesity, previous damage to the kidneys, and older age. The albumin/creatinine ratio is an important part of this assessment [2,3].
Microalbuminuria is a known risk factor for progressive kidney disease and cardiovascular death [4]. The National Kidney Foundation (NKF) recommends annual testing for microalbumin/albumin in all individuals with diabetes whose kidneys are functioning. According to the NKF, annual testing should start 5 years after diagnosis for individuals with type 1 diabetes and at diagnosis for individuals with type 2 diabetes [5].
The NKF recommends that at least 2 of 3 specimens, drawn within a 3- to 6-month period, be reported as abnormal before making a clinical diagnosis of either microalbuminuria or albuminuria [5]. Results are reported as a ratio of albumin (µg) to creatinine (mg).
Test results should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Burtis C, et al. Amino acids and proteins. In: Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 7th ed. St Louis, MO: Elsevier; 2015:314-315.
2. Gaitonde DY, et al. Am Fam Physician. 2017;96:776-783.
3. Centers for Disease Control and Prevention. Chronic kidney disease in the United States, 2019. https://www.cdc.gov/kidneydisease/publications-resources/2019-national-facts.html. Last reviewed March 11, 2019. Accessed February 4, 2020.
4. Weir, MR. Clin J Am Soc Nephrol. 2007;2:581-590.
5. National Kidney Foundation. Am J Kidney Dis. 2007(Suppl 2);49:S1-S180.
