The analysis and characterisation of immuno-unreactive urinary albumin in healthy volunteers.
OBJECTIVE
To compare the analysis of different forms of intact albumin in urine from healthy volunteers. To determine contamination by common non-albumin proteins on HPLC analysis of urinary albumin and of purified immuno-unreactive albumin.


METHODS
Overnight urine samples collected from healthy volunteers were analysed for total albumin (immunoreactive plus immuno-unreactive) by HPLC and densitometry following native PAGE separation and for immunoreactive albumin by RIA. The contamination by non-albumin proteins of the HPLC analysis of urinary albumin and of immuno-unreactive albumin preparations was determined by ELISA. Immuno-unreactive albumin was tested for Co2+-binding capacity.


CONCLUSIONS
HPLC analysis of healthy urine generates higher ACR values than immunological methods due to the presence of immuno-unreactive albumin. Immuno-unreactive albumin cannot be accounted for by the non-albumin urinary proteins tested. Isolated immuno-unreactive albumin is not recognised by antibodies to common urinary proteins or by an array of anti-albumin antibodies and behaves like serum albumin in terms of HPLC elution, native PAGE migration, and cobalt ion binding.
Clavant
Steven P
SP
AusAm Biotechnologies Inc., New York, NY 10022, USA.
Sastra
Steve A
SA
Osicka
Tanya M
TM
Comper
Wayne D
WD
D000293:Adolescent; D000328:Adult; D000368:Aged; D000419:Albuminuria; D000911:Antibodies, Monoclonal; D002851:Chromatography, High Pressure Liquid; D003035:Cobalt / Q000737:chemistry; D003404:Creatinine / Q000652:urine; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011507:Proteinuria; D011863:Radioimmunoassay; D016482:Urinalysis / Q000379:methods*
D000911:Antibodies, Monoclonal; D003035:Cobalt; D003404:Creatinine