α1-Acid glycoprotein decreases recovery of total protein in urine when trichloroacetic acid is used to precipitate the proteins

J. P. Beilby; B. A. O'Leary

doi:10.1093/clinchem/36.3.565

α₁-Acid glycoprotein decreases recovery of total protein in urine when trichloroacetic acid is used to precipitate the proteins

J. P. Beilby, B. A. O'Leary

Research output: Contribution to journal › Article › peer-review

5 Citations (Scopus)

Abstract

Total urine protein was measured in 132 samples by an automated benzethonium chloride method and the Ponceau-S/trichloroacetic acid (PS/TCA) method. Of these, 27% gave a result 0.1 g/L or more higher by the benzethonium chloride method. Of this 27%, most contained an abnormally high concentration of the acute-phase reactant, α₁-acid glycoprotein. By assaying urine containing added α₁-acid glycoprotein and albumin, we found that α₁-acid glycoprotein causes the PS/TCA method to underestimate the total urine protein concentration, whereas the benzethonium chloride method is unaffected. Not all urinary albumin was precipitated by TCA when α₁-acid glycoprotein was present. Therefore, protein methods in which trichloroacetic acid is used as a concentrating step before the assay will underestimate total urine protein when the concentration of α₁-acid glycoprotein is high.

Original language	English
Pages (from-to)	565-657
Number of pages	93
Journal	Clinical Chemistry
Volume	36
Issue number	3
DOIs	https://doi.org/10.1093/clinchem/36.3.565
Publication status	Published - 1990
Externally published	Yes

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title = "α1-Acid glycoprotein decreases recovery of total protein in urine when trichloroacetic acid is used to precipitate the proteins",

abstract = "Total urine protein was measured in 132 samples by an automated benzethonium chloride method and the Ponceau-S/trichloroacetic acid (PS/TCA) method. Of these, 27% gave a result 0.1 g/L or more higher by the benzethonium chloride method. Of this 27%, most contained an abnormally high concentration of the acute-phase reactant, α1-acid glycoprotein. By assaying urine containing added α1-acid glycoprotein and albumin, we found that α1-acid glycoprotein causes the PS/TCA method to underestimate the total urine protein concentration, whereas the benzethonium chloride method is unaffected. Not all urinary albumin was precipitated by TCA when α1-acid glycoprotein was present. Therefore, protein methods in which trichloroacetic acid is used as a concentrating step before the assay will underestimate total urine protein when the concentration of α1-acid glycoprotein is high.",

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AU - O'Leary, B. A.

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N2 - Total urine protein was measured in 132 samples by an automated benzethonium chloride method and the Ponceau-S/trichloroacetic acid (PS/TCA) method. Of these, 27% gave a result 0.1 g/L or more higher by the benzethonium chloride method. Of this 27%, most contained an abnormally high concentration of the acute-phase reactant, α1-acid glycoprotein. By assaying urine containing added α1-acid glycoprotein and albumin, we found that α1-acid glycoprotein causes the PS/TCA method to underestimate the total urine protein concentration, whereas the benzethonium chloride method is unaffected. Not all urinary albumin was precipitated by TCA when α1-acid glycoprotein was present. Therefore, protein methods in which trichloroacetic acid is used as a concentrating step before the assay will underestimate total urine protein when the concentration of α1-acid glycoprotein is high.

AB - Total urine protein was measured in 132 samples by an automated benzethonium chloride method and the Ponceau-S/trichloroacetic acid (PS/TCA) method. Of these, 27% gave a result 0.1 g/L or more higher by the benzethonium chloride method. Of this 27%, most contained an abnormally high concentration of the acute-phase reactant, α1-acid glycoprotein. By assaying urine containing added α1-acid glycoprotein and albumin, we found that α1-acid glycoprotein causes the PS/TCA method to underestimate the total urine protein concentration, whereas the benzethonium chloride method is unaffected. Not all urinary albumin was precipitated by TCA when α1-acid glycoprotein was present. Therefore, protein methods in which trichloroacetic acid is used as a concentrating step before the assay will underestimate total urine protein when the concentration of α1-acid glycoprotein is high.

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α₁-Acid glycoprotein decreases recovery of total protein in urine when trichloroacetic acid is used to precipitate the proteins

Abstract

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