3.1 | Study selection
A systematic literature search was
conducted, resulting in a total of 4,600 records. After excluding 4,497
citations based on title and abstract, 103 full-text publications were
selected for a secondary review. Ultimately, nine studies that were
relevant to the diagnostic accuracy of sIgE to milk components for milk
allergy were included [30-38]. The selection
process is illustrated in Figure 1.
3.2 | Characteristics of included studies
Table 1 presents a summary of the
main characteristics of the nine studies included in this analysis. A
total of 958 participants were recruited across these studies, with five
of them [31, 32, 34, 36, 37] conducted in Europe,
two in South America [33, 35], and two in Asia[30, 38]. Of the nine studies, five were
prospective [30, 31, 34, 35, 38], two were
retrospective [33, 37], and two were case-control
designs [32, 36]. Our literature search did not
impose any age restrictions, but none of the studies on adults met the
inclusion criteria. Therefore, all the included studies were conducted
on children, with participants aged between 2 months and 16.7 years. At
least one milk allergy component was used in the diagnostic accuracy
analysis of CRD across all the included studies. Three of the studies
used a blinded approach [30, 31, 37] (single- or
double-blind) for OFC, and 321 (78.9%) of 407 patients with suspected
CM allergy tested positive for OFC. Five studies [32,
34-36, 38] did not use blinding for OFC, and 428 patients received
milk OFC, with 268 (62.6%) showing a positive reaction. In a study of
CM allergy involving 123 patients [33], 26 (21%)
underwent DBOFC, 51 (41%) underwent unblinded OFC, and the remaining
patients did not undergo OFC. The thresholds for the fractions varied
across studies and fractions. Five studies used the immunocap method to
determine sIgE levels [32, 33, 35, 36, 38], one
study used the microarray technique (ISAC CRD
51)[37], two studies used both ImmunoCAP and
microarray technology[31, 34], one study used
both ImmunoCAP and 3gAllergy technology.[30]
FIGURE 1 PRISMA Diagram for the
literature search
3.3 | Quality assessment of included studies
Figure 2 summarizes the QUADAS-2 quality assessment for each study.
Detailed QUADAS-2 assessment results are provided in Supplementary
Information Table S3.