A micro-method for measuring total protein in cerebrospinal fluid by using benzethonium chloride in microtiter plate wells.
By using a benzethonium chloride concentration 12-fold that described originally (Clin Chem 1979;25:1317-9), we developed a reliable method suitable for routine measurement of total protein in cerebrospinal fluid. Only 10 microL of sample is required. Reactivity to immunoglobulin G (IgG) and to albumin (Alb) is similar, as is necessary for specimens that can have very varied IgG/Alb ratios. The assay, performed in a microtiter plate for ease of use, has a between-batch coefficient of variation of 3.4% for a protein concentration of 450 mg/L. This contrasts with a dye-binding technique with Ponceau S, for which the CV was 9% at the same concentration.
Luxton
R W
RW
Department of Special Chemical Pathology, National Hospitals for Nervous Diseases, London, England.
Patel
P
P
Keir
G
G
Thompson
E J
EJ
D000418:Albumins / Q000134:cerebrospinal fluid; D001391:Azo Compounds; D001558:Benzethonium; D002556:Cerebrospinal Fluid Proteins / Q000032:analysis*; D006801:Humans; D000644:Quaternary Ammonium Compounds; D014168:Transferrin / Q000134:cerebrospinal fluid; D005719:gamma-Globulins / Q000134:cerebrospinal fluid
D000418:Albumins; D001391:Azo Compounds; D002556:Cerebrospinal Fluid Proteins; D000644:Quaternary Ammonium Compounds; D014168:Transferrin; D005719:gamma-Globulins; D001558:Benzethonium; C032756:ponceau S