SOLID-PHASE RADIOIMMUNOASSAY FOR MEASUREMENT OF LACTOFERRIN IN HUMAN-PLASMA - VARIATIONS WITH AGE, SEX, AND DISEASE

Abstract

A solid-phase radioimmunoassay is described for measuring lactoferrin levels in normal human plasma. The sensitivity of the assay was 6 ng/ml with an intraassay coefficient of variation of 4% and an interassay value of 9%. Healthy adult males had a mean plasma level of 1.62 .mu.g/ml which was significantly higher than adult females, 1.07 .mu.g/ml. Postmenopausal females had levels similar to men, 1.74 .mu.g/ml, while younger women had a significantly lower mean value, 0.75 .mu.g/ml. Two menstruating women and 2 pregnant women had moderately elevated levels. Consistently elevated levels were found in patients with untreated or relapsing chronic myeloid leukemia, all over 12.0 .mu.g/ml, while patients on marrow suppressant therapy tended to have subnormal levels. The collection of serum specimens as opposed to plasma, resulted in inconsistently elevated levels; EDTA was the anticoagulant of choice, as heparin interfered in the radioimmunoassay system.