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A rapid, accurate, precise assay for determination of plasma transferrin
Author(s) -
Leonberg BL,
Crosby LO,
Buzby GP
Publication year - 1987
Publication title -
journal of parenteral and enteral nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.935
H-Index - 98
eISSN - 1941-2444
pISSN - 0148-6071
DOI - 10.1177/014860718701100174
Subject(s) - radial immunodiffusion , chromatography , transferrin , reference range , chemistry , coefficient of variation , medicine , antibody , immunology
Plasma transferrin (TFN) levels are valid as markers of protein‐calorie malnutrition (PCM). Current methods for determining TFN, specifically, radial immunodiffusion (RID) plates or derivation from total iron‐binding capacity (TIBC), are relatively expensive, time consuming (20–50 hr) and technically demanding, limiting the use of TFN levels in the routine screening for PCM. A rapid (60–90 min), accurate and precise TFN assay, easily performed with common laboratory equipment, was developed for use in a study of hospitalized patients. This assay requires 15 microliter of plasma and is based on an antigen‐antibody reaction using commercially available TFN antibody. After a 30‐min incubation, turbidity is measured at 413 nm on a spectrophotometer with a 1‐cm path length. Values by this method are linear over the range of 50–760 mg/dl. Plasma samples (n = 72) were assayed for TFN by this turbidimetric (TURB) technique and the standard RID technique. Correlation between the two assays was r = 0.942 over the range of TFN = 81–403 mg/dl (TFNRID = 30.7 + (0.931) TFNTURB). Coefficient of variation (CV) for TFNTURB was 4.0%. RID kit insert reports a CV = 2.9% at a value of 380 mg/dl. This assay overcomes many of the difficulties associated with TFN determination by RID or derived from TIBC and may allow more widespread application of plasma TFN levels as a clinically relevant PCM screening tool.