ONE-STEP URINARY ALBUMIN CASSETTE TEST
Name and Intended Use
The one-step Urinary Albumin Cassette Test is a colloidal gold/antibody complex based
immunoassay designed for the semi-quantitative determination of human serum albumin
(HSA) in urine. It is intended for the early detection of microalbuminuria (slightly
elevated quantities of albumin in urine) before the appearance of overt symptoms of renal
disease.
Summary and Explanation of the Test
Microalbuminuria (MAU) is associated with the development of clinical proteinuria,
chronic renal failure, and premature cardiovascular mortality in patients with insulindependent, type I diabetes mellitus. MAU is also associated with cardiovascular
morbidity and mortality in patients with non-insulin dependent, type II diabetes mellitus.
In addition, MAU has received increasing attention as a risk indicator in hypertensive
patients without diabetes mellitus. Therefore, an increase in urinary albumin excretion
has an important predictive value, and it affords the opportunity, through treatment, to
slowdown the progression of disease.
However, the level of urinary HSA above which renal disease is likely to develop is still
not clearly defined. In many studies, there is a range of threshold urinary albumin
between 12-18 g/mL. Microalbuminuria 20 g/mL and above is a good predictor of
diabetic nephropathy.
Principles of the Procedure
The one-step Urinary Albumin Cassette Test strip consists of a chromatographic
absorbent device and a specific monoclonal antibody against human serum albumin. In
three minutes, elevated levels of HAS in the urine is detected.
The urine migrates through the absorbent area and along the test membrane. HSA
present in the urine is bound to the antibody-dye conjugate forming an antibody-antigen
complex. In zone (T) of the membrane, immobilized human albumin capture free
antibody-gold conjugate not already bound to analyte from the urine sample. As a
consequence of this, the more HSA in the urine sample, the lighter the pink-rose color in
the zone (T) will be. The gold-conjugate not bound in zone (T) is captured by the nonspecific antibody immobilized in the control zone (C) of the membrane, and the more
HSA in the urine sample, the darker the pink-rose color in the zone (C) will be.
Stability and Storage
The one-step Urinary Albumin Cassette Test strips are stable at 18-28oC until the expiry
date.
Interfering Substances
The cross reactivity of the VBL one-step Urinary Albumin Cassette Test with common
human proteins and medications was tested in negative levels of microalbuminuria:
Substance
Acetaminophen
Ascorbic Acid
Caffeine
Gentistic Acid
Hemoglobin
Uric Acid
Urea
Atropine
Level Tested
20 mg/mL
40 mg/mL
40 mg/mL
40 mg/dL
10 mg/dL
10 mg/dL
4000 mg/dL
40 mg/dL
Interference @ 0 g/mL
No
No
No
No
No
No
No
No
It is known that Bovine Serum Albumin (BSA) is cross reactive with the test, and thus,
high levels of meat in the diet may cause a false test result.
Specimen Collection
Two urine samples must be taken one of four ways: a) early morning collections, b)
collections within 24 hours, c) overnight collection with at least 8 hours between the
samples, and d) one to two hour collections. Two samples must be taken because of
individual urine deviation. If the results of the two samples are not in agreement with
one another, a third urine sample must be taken as well. Store the urine specimens at 4oC
for up to 14 days (do not freeze).
Materials
(provided)
- One-step Urinary Albumin Cassette Test
(Not provided)
-Pipette with 0.1 mL increment
-Urine samples
-Timer
Procedure
1. Remove test device ( One-step Urinary Albumin Cassette test) from the pouch.
2. Bring the test device to room temperature.
3. Place the test device on a flat surface, and apply 0.1 mL of urine specimen to the
sample well (S).
4. Allow the test to run for 3 minutes, and then read the results.
Interpretation
If the band intensity of the control and the test are equal in intensity, the sample
concentration of urinary albumin is 15 g/mL. If the band intensity of the test line is
stronger than the control line, then the concentration of urinary albumin is 10 g/mL or
less (negative result). If the band intensity of the control line is stronger than the test line,
then the concentration of urinary albumin is 20 g/mL or more (positive result). If one
can only see a control line, this is also a positive result. In all circumstances, if one
cannot see either a control line or a test line, the test is invalid and must be re-run. Do not
read the test result after three minutes (See figure 1).
Figure 1. Test results with varying Urinary Albumin concentrations.
References
1.
2.
3.
4.
5.
Agrawal et al. Journal of Hypertension; 14: 223-228 (1996)
Viberti et al. Lancet; I: 1430-1432 (1982)
Parving et al. Acta Endocrinol (Copenh); 100: 550-5 (1982)
Christensen et al. Diabetes; 32: Suppl 2: 64-78 (1983)
Morgensen etal. N Engl J Med; 311: 89-93 (1984)
Last Revised: May 26, 2005