Usefulness of Diagnostic Tests in Cows' Milk Allergy

Abstract

RATIONALE: Different cutoff values for skin prik test (SPT) and specific IgE levels have been previously given to predict a positive food challenge test in milk (CM) allergy.METHODS: A transversal study including CM allergic children. After six months of milk-excluding-diet a complete anamnesis, SPT and specific IgE with CM and fractions were determinated. Simpled-blind controlled food challenge (SBCFC) were performed in children with specific IgE lower than 2.5 KU/l. The others continued with milk-excluding-diet and after 6 months were asked for any transgression in diet. We considered this transgresions as a food oral chalenge test at home.RESULTS: 162 children were included. Only 85 children had specific IgE lower than 2.5KU/l and a SBCFC was performed. 54 tolerated (63.5%). 77 continued without CM.13 had a symptomatic transgresion (possitive chalenge). Best cutoff points for SPT to milk and fractions were 3mm, except for alfalactoalbumine (6mm). The cutoff value 2,5 Ku/l of CM specific-IgE in our study had a specificty of 79,2% and a negative predictive value of 60%.Differences in accuracy were obteined to SPT and milk specific IgE between older and younger than one year. CM SPT ROC area was 0.54 in <1 year and 0.80 in >1year, and milk specific IgE ROC area was 0.40 in <1 year and 0.75 in >1 year.CONCLUSIONS: The accuracy of previously given 2,5 Ku/l cutoff point for specific IgE in the patient management in clinical practice was similar to published studies in clinical research conditionts. Test accuracy was higher in children older than 1 year. RATIONALE: Different cutoff values for skin prik test (SPT) and specific IgE levels have been previously given to predict a positive food challenge test in milk (CM) allergy. METHODS: A transversal study including CM allergic children. After six months of milk-excluding-diet a complete anamnesis, SPT and specific IgE with CM and fractions were determinated. Simpled-blind controlled food challenge (SBCFC) were performed in children with specific IgE lower than 2.5 KU/l. The others continued with milk-excluding-diet and after 6 months were asked for any transgression in diet. We considered this transgresions as a food oral chalenge test at home. RESULTS: 162 children were included. Only 85 children had specific IgE lower than 2.5KU/l and a SBCFC was performed. 54 tolerated (63.5%). 77 continued without CM.13 had a symptomatic transgresion (possitive chalenge). Best cutoff points for SPT to milk and fractions were 3mm, except for alfalactoalbumine (6mm). The cutoff value 2,5 Ku/l of CM specific-IgE in our study had a specificty of 79,2% and a negative predictive value of 60%. Differences in accuracy were obteined to SPT and milk specific IgE between older and younger than one year. CM SPT ROC area was 0.54 in <1 year and 0.80 in >1year, and milk specific IgE ROC area was 0.40 in <1 year and 0.75 in >1 year. CONCLUSIONS: The accuracy of previously given 2,5 Ku/l cutoff point for specific IgE in the patient management in clinical practice was similar to published studies in clinical research conditionts. Test accuracy was higher in children older than 1 year.