| Microalbumin:Creatinine Ratio, Random
Urine |
| |
|
| CPT |
|
82043;
82570 |
| Synonyms |
|
Albumin:Creatinine Ratio, Random
Urine |
| Test
Includes |
|
Microalbumin, random urine; creatinine;
albumin:creatinine ratio |
| Specimen |
|
Urine
(random) |
| Volume |
|
10 mL |
| Minimum
Volume |
|
2 mL (Note: This volume does not allow
for repeat testing.) |
| Container |
|
Plastic urine
container |
| Collection |
|
Collect random urine without
preservative. |
| Storage
Instructions |
|
Refrigerate |
| Causes for
Rejection |
|
Bloody
specimen |
| Reference
Interval |
|
- Normal: 0-30 µg/mg creatinine
- Microalbuminuria: 30-300 µg/mg creatinine
- Clinical albuminuria: >300 µg/mg
creatinine
|
| Use |
|
Measurement of albumin levels in urine below the
detection level of urine dipsticks. This test is useful in the management of
patients with relatively early diabetes mellitus to assist in avoiding or
delaying the onset of diabetic renal
disease. |
| Limitations |
|
Because of the inherent day-to-day variability of
albumin excretion into the urine, two of three microalbumin levels measured
within a 3- to 6-month period should be abnormal before a considering a patient
to have crossed a diagnostic threshold.1
Physical exercise during the previous 24 hours can cause a transient elevation
in microalbumin. Other variables, including infection, fever, congestive heart
failure, marked hyperglycemia, and marked hypertension, can result in increased
microalbumin levels. |
| Methodology |
|
Microalbumin: immunoturbidimetric; creatinine:
kinetic |
| Additional
Information |
|
Albumin accounts for approximately 50% of the protein
in plasma.2 The kidney works to prevent the loss
of albumin into the urine through active resorbtion, but a small amount of
albumin can be measured in urine of individuals with normal renal function.
Microalbumin is the term ascribed to the measurement of albumin in urine at
concentrations below the sensitivity of dipstick tests for total protein.
Microalbuminuria (ie, urine albumin levels above the reference range and below
the level of clinical albuminuria) is a important indicator of deteriorating
renal function.
The prognostic value of consistently elevated microalbumin levels is
particularly well established in diabetic patients.1 Renal disease is a common microvascular complication
of diabetes. Without specific interventions, 80% of type I diabetics with
repeatedly elevated microalbumin levels will go on to end-stage renal disease.
Twenty percent to 40% of type II diabetics with sustained microalbuminuria will
progress to overt nephropathy.
The American Diabetes Association (ADA) recommends that routine urinalysis
should be performed annually on adults with diabetes.1 If the urinalysis is negative for protein,
microalbumin measurement is recommended. The ADA also recommends annual
screening of children beginning at puberty or after 5 years of disease duration.
The reference intervals stated above reflect the diagnostic criteria prescribed
by the ADA.1
|