Diagnostic cut‐off of Aspergillus fumigatus‐specific IgG in the diagnosis of chronic pulmonary aspergillosis

Abstract

Aspergillus fumigatus-specific IgG is pivotal in making the diagnosis of chronic pulmonary aspergillosis (CPA). However, the cut-off value for A. fumigatus-specific IgG remains unknown. We included consecutive treatment-naïve subjects with chronic cavitary pulmonary aspergillosis (CCPA, cases). The controls were subjects with treated pulmonary tuberculosis, who had residual radiological abnormality and minimal symptoms. The diagnosis of CCPA was based on consistent clinicoradiological features along with demonstration of Aspergillus infection (growth of Aspergillus in sputum or bronchoalveolar lavage fluid [BALF] culture; serum or BALF galactomannan index >0.5 and >1, respectively). For determining the cut-off of A. fumigatus-specific IgG (Phadia), subjects were randomly classified as derivation (two-thirds) and validation (one-third) cohort. One hundred and thirty-seven cases and 50 controls were included. The best cut-off value for A. fumigatus-specific IgG (derivation cohort) was 27.3 mgA/L (AUROC, 0.976) at a sensitivity and specificity of 95.6% and 100%, respectively. Using a cut-off of 27 mgA/L, the sensitivity and specificity in the validation cohort was 91.3% and 100%, respectively. In contrast, the sensitivity of Aspergillus precipitins was only 25.5%. At a cut-off value of 27 mgA/L, A. fumigatus-specific IgG is a reliable test with high sensitivity and specificity in the diagnosis of CPA. More studies are required to confirm our findings.

Efficiency of A fumigatus‐specific IgG and galactomannan testing in the diagnosis of simple aspergilloma

“…In the current study, A fumigatus ‐specific IgG had a moderate sensitivity but excellent specificity for diagnosing SA. Although the cut‐off value is similar to that used in other forms of chronic aspergillosis (CCPA and ABPA), the lower sensitivity is possibly due to the saprophytic nature of the infection …”

“…The Institute Ethics Committee approved the study protocol, and a written informed consent was obtained from all the study participants. Some of the data have been previously published …”

Accuracy of serological tests for diagnosis of chronic pulmonary aspergillosis: a systematic review and meta-analysis

“…The characteristics of the included studies are presented in S1Table. The earliest study was published in 1983 [22] and the five most current articles were published in 2015 [23], 2016 [24, 25, 26] and 2018 [27]. Nine studies took place in five countries: Japan [25, 28], Brazil [23], United Kingdom [24, 29], France [26, 30, 31] and India [27], but in 4 articles, the study countries were not reported [22, 32, 33, 34].…”

“…Nine articles presented DID as the reference test [22, 23, 25, 27, 28, 30, 32, 33, 34]; an article presented two reference tests, DID and CIE [34] and four studies presented only CIE as the reference test [24, 26, 29, 31].…”

“…When we performed data extraction, some important differences were observed and deserve to be highlighted. Seven articles performed in-house ELISA tests [22, 23, 28, 30, 32, 33, 34] and six articles described their studies with commercial tests [24, 25, 26, 27, 29, 31]. Different Aspergillus antigens and cut-off points were used in the in-house ELISA tests; the articles that used commercial tests also used several types of antigens and cutoff points included by authors beyond those established by the manufacturer and are described in S1 Table.…”