Measurement of the albumin content of urinary protein using dipsticks

Abstract

An albumin selective urine strip based on bis (3',3''-diiodo-4', 4''-dihydroxy-5',5''-dinitrophenyl)-3,4,5,6-tetrabromo sulfonphthalein dye (DIDNTB) dye was examined in populations with clinical proteinuria. The relationship of albumin to the sum concentration of all protein in urine was found to vary widely even though the albumin concentration generally increased with the total protein concentration. The albumin reagent strips correlated well with immuno-nephrometric assays for albumin on specimens from hypertensives, diabetics, and renal disease which tended to have albumin contents of >/= 50.0%. High proteinuria concentrations of > 250 mg/l, with low albumin contents of </= 30%, occurred more frequently in cases of cancer, infection, and myeloma. The albumin strip read higher than the immuno assay in samples with high proteinuria and low albuminuria. The albumin strip was also less affected by albumin fragmentation than by the immunological assay. Overall, the albumin strip gave a lower risk of false negatives than a protein strip based on tetrabromophenol blue (TBPB) dye and was more sensitive to disease condition. The protein strip was not sensitive to low levels of albumin and the agreement between TBPB dye strip and the quantitative analysis was not as affected by the albumin content.

Variation in the Urinary Protein/Creatinine Ratio at Four Different Periods of the Day in Hypertensive Pregnant Women

“…Patients with low urinary output may test positive with the dipsticks even when protein excretion is normal; the opposite being true in patients with increased protein excretion and high urine output (2)(3)(4)(5). Falsepositive tests also occur when ketonuria is present (6).…”

A novel lab-on-a-chip design by sequential capillary–gravitational valves for urinary creatinine detection

“…There is a semi-quantitative approach that uses the reagent strip (dipstick) for a POCT that is sufficiently sensitive to microalbumin [8]. However, the dipstick method is not well accepted for medical evaluation and prognosis because of the low correlation of its results with low microalbumin concentration [9]. Normalization by an internal factor of spot urine is therefore necessary.…”