Serum Aspergillus galactomannan lateral flow assay for the diagnosis of invasive aspergillosis: A single‐centre study

Abstract

Background Aspergillus species meet the most important group of invasive fungal diseases (IFD) in immunosuppressed patients. Galactomannan is a polysaccharide antigen located in the wall structure of Aspergillus. The most commonly used method for antigen detection is enzyme‐linked immunoassay (ELISA). Aspergillus galactomannan lateral flow assay (LFA) constitutes one of the new methods in the diagnosis of invasive aspergillosis (IA). The goal of this study was to demonstrate efficacy of LFA in our patients and to compare it to synchronous ELISA results. Methods Galactomannan antigen was examined using both LFA and ELISA in serum samples taken from patients who were followed up in our haematology clinic. All patients are classified in subgroups as ‘proven’, ‘probable’ and ‘possible’ patients according to the last EORTC / MSG guideline. Patients who met the ‘proven’ IA criteria were included in the study as the gold standard. Results A total of 87 patients were included in the study. Majority of patients had acute myeloid leukaemia (AML) (56.3%). Eleven (12.6%) were in ‘proven’ IA group. LFA test showed a superior diagnostic performance compared with ELISA (LFAAUC = 0.934 vs ELISAAUC = 0.545; p < .001). The LFA had a sensitivity of 90.9% and a specificity of 90.8% for ‘0.5 ODI’ in predicting IA (PPV = 55.8%; NPV = 98.6%; p < .001). Conclusion The most important finding of this study is that the specificity of LFA was found to be higher for cut‐off value of 0.5. It is recommended to combine the methods in many studies to provide a better early diagnosis for IA.

Serum Lateral Flow assay with digital reader for the diagnosis of invasive pulmonary aspergillosis: A two‐centre mixed cohort study

“…At a 0.5 ODI cut‐off the overall sensitivity and specificity was 78.6% and 80.5%, respectively, in differentiating probable/proven disease versus no aspergillosis with similar performance in patients without haematological malignancies (eg, 83.3% sensitivity and 75.9% specificity in those with other established risk factors for IA but without haematologic malignancy), which represented 55% of our study cohort. Previously the LFA with automated read out was evaluated exclusively in serum samples from patients with haematological malignancies, where two studies found higher sensitivity and specificity 16,17 and one a lower sensitivity, compared to our findings 14 …”

“…Previously the LFA with automated read out was evaluated exclusively in serum samples from patients with haematological malignancies, where two studies found higher sensitivity and specificity 16,17 and one a lower sensitivity, compared to our findings. 14 The serum LFA has several advantages over GM ELISA testing, including that it allows for single sample testing, requires minimal laboratory equipment so can potentially be performed at a lower cost than ELISA testing, and has shorter turn-around times, making it an attractive option for smaller centres that don't test GM in house.…”

“… 10 , 11 , 12 , 13 A recent multicentre study in a mixed cohort of patients found a sensitivity of 74% and specificity of 83% with digital readout from BALF at an optical density cut‐off (ODI) of 1.5, with stable test performance across centres and patient groups. 14 In serum, the LFA with digital readout was evaluated in three studies focusing exclusively on patients with haematologic malignancy, with one study reporting a sensitivity of 49% and a specificity of 95%, 15 and two reporting higher sensitivities of 96.9% 16 and 90.9% 17 with specificities between 90% and 96% at an ODI of ≥0.5. However, evaluation of the LFA test with digital readout from serum outside the haematologic malignancy setting is lacking.…”

Aspergillus Lateral Flow Assay with Digital Reader for the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis (CAPA): a Multicenter Study

“…In serum, the LFA with digital readout was evaluated in four studies focusing mostly on patients with hematologic malignancy. Among hematological malignancy patients one study reported a sensitivity of 49% and a specificity of 95% ( 21 ), and two reported higher sensitivities of 97% ( 22 ) and 91% ( 23 ) with specificities between 90% and 96% at an ODI of ≥0.5, reaching 100% at 0.61 ODI cutoff ( 22 ). In a recent mixed cohort study, sensitivity and specificity of the LFA were 78.6% and 80.5% a 0.5 ODI cutoff, with similar performance among patients with hematological malignancies and patients with other traditional risk factors for IA ( 24 ).…”

Lateral flow assay (LFA) in the diagnosis of COVID-19-associated pulmonary aspergillosis (CAPA): a single-center experience

“…In a study from our clinic, the diagnostic efficiency of LFA and ELISA were evaluated simultaneously for 87 patients diagnosed with hematological malignancy. LFA was more specific than ELISA in terms of the cutoff value of 0.5 optical density index (ODI) [20].…”