Evaluation of the MAST CLA Assay System for Measuring Total IgE: Comparison with the Pharmacia CAP System

Cha, Young Joo; Chae, Seok Lae; Park, Ae Ja

Abstract

BACKGROUND
Multiple allergosorbent test chemiluminescent assay (MAST CLA) is a simple method for measuring total and allergen-specific IgE in human serum. Total IgE level, however, was much frequently high, even if no allergen-specific IgE could be detected in serum. The aim of this study was to evaluate the total IgE class of the MAST CLA system.
METHODS
We studied 649 patients in whom MAST CLA (MAST Immunosystems, Inc., Mountain View, CA, USA) was tested and compared the results with those of total IgE, Phadiatop FEIA & RAST FEIA using Pharmacia CAP system (Pharmacia AB, Uppsala, Sweden).
RESULTS
MAST CLA specific IgE was positive in 139 (21.4%) among 649 patients. Total IgE was increased over class 2 in 379 (74.3%) among 510 MAST CLA allergen-specific IgE -negative patients. Total IgE assayed by Pharmacia CAP system was increased over 100 kU/L in 33 (54.1%) among 61 MAST CLA allergen-specific IgE -negative patients. Especially, total IgE assayed by Pharmacia CAP system was increased over 100 kU/L in 25 (69.4%) of 36 patients when MAST CLA total IgE class is over 2. Phadiatop FEIA which is a screening test for inhalant allergy was positive in 11 (50.0%) of 22 MAST CLA allergen-specific IgE -negative patients, and especially, positive in 8 (66.7%) of 12 MAST CLA allergen-specific IgE -negative patients who had MAST CLA total IgE class over 2. Nine of 11 patients with positive Phadiatop FEIA were also found to be positive in d1 and/or d2 by RAST FEIA.
CONCLUSIONS
It is concluded that another allergen screening tests should be used for detecting allergen-specific IgE, when MAST CLA total IgE is increased over class 2 with no detectable MAST CLA specific IgE because the sensitivity of MAST CLA allergen-specific IgE could be low.