Rapid assay of lactoferrin in keratoconjunctivitis sicca.

We compared measurement of lactoferrin concentration by the LactoCard solid phase ELISA assay with the LactoPlate radial immunodiffusion assay in tears of normal patients and those with keratoconjunctivitis sicca. The LactoCard, a new lactoferrin assay, allows rapid determination of tear lactoferrin concentration in 10-15 min, a notable improvement over the 3 days required of the LactoPlate. There was no statistically significant difference between the accuracy of the two assays in normal patients nor in those patients with a diagnosis of keratoconjunctivitis sicca. Both assays showed a significant decrease in tear lactoferrin concentration in patients with severe keratoconjunctivitis sicca when compared to normal patients. The LactoCard is a rapid and reliable means of measuring tear lactoferrin concentration in a clinical setting.