Development and Evaluation of Europium-Based Quantitative Lateral Flow Immunoassay for the Chronic Kidney Disease Marker Cystatin-C

Improving African Swine Fever Surveillance Using Fluorescent Rapid Tests

African swine fever (ASF) is a viral disease of swine with a huge impact due to its high mortality. Lately, the disease has actively spread around the world, affecting new areas from which it had been eradicated long ago. To date, ASF control is carried out by the implementation of strict biosecurity measures such as the early identification of infected animals. In this work, two fluorescent rapid tests were developed to improve the sensitivity of point-of-care diagnosis of ASF. For antigen (Ag) detection in blood, a double-antibody sandwich fluorescent lateral flow assay (LFA) was developed, employing a newly developed recombinant antibody to the VP72 of the virus. To complement the diagnosis, a double-recognition fluorescent LFA was developed using the VP72 for the detection of specific antibodies (Ab) in sera or blood. Both assays statistically improved the detection of the disease when compared to the commercial colorimetric assays INgezim^® ASFV CROM Ag and INgezim^® PPA CROM Anticuerpo, respectively, with higher statistical significance between 11 and 39 days post-infection. From the observation of results, it can be concluded that the combination of both Ag-LFA and Ab-LFA assays would facilitate the identification of infected animals, regardless of post-infection time.

Development of a quantitative fluorescence lateral flow immunoassay (LFIA) prototype for point-of-need detection of anti-Müllerian hormone

Objective

Anti-Müllerian Hormone (AMH) is a quantitative marker for ovarian reserve and is used to predict response during ovarian stimulation. Streamlining testing to the clinic or even to the physician's office would reduce inconvenience, turnaround time, patient stress and potentially also the total cost of testing, allowing for more frequent monitoring. In this paper, AMH is used as a model biomarker to describe the rational development and optimization of sensitive, quantitative, clinic-based rapid diagnostic tests.

Design and Methods

We developed a one-step lateral-flow europium (III) chelate-based fluorescent immunoassay (LFIA) for the detection of AMH on a portable fluorescent reader, optimizing the capture/detection antibodies, running buffer, and reporter conjugates.

Results

A panel of commercial calibrators was used to develop a standard curve to determine the analytical sensitivity (LOD = 0.41 ng/ml) and the analytical range (0.41-15.6 ng/ml) of the LFIA. Commercial controls were then tested to perform an initial evaluation of the prototype performance and showed a high degree of precision (Control I CV 2.18%; Control II CV 3.61%) and accuracy (Control I recovery 126%; Control II recovery 103%). Conclusions: This initial evaluation suggests that, in future clinical testing, the AMH LFIA will likely have the capability of distinguishing women with low ovarian reserve (<1 ng/ml AMH) from women with normal (1-4 ng/ml AMH) ovarian reserve. Furthermore, the LFIA demonstrated a wide linear range, indicating the assay's applicability to the detection of other health conditions such as PCOS, which requires AMH measurement at higher concentrations (>6 ng/ml).

Lateral flow assays for detection of disease biomarkers

Early diagnosis saves lives in many diseases. In this sense, monitoring of biomarkers is crucial for the diagnosis of diseases. Lateral flow assays (LFAs) have attracted great attention among paper-based point-of-care testing (POCT) due to their low cost, user-friendliness, and time-saving advantages. Developments in the field of health have led to an increase of interest in these rapid tests. LFAs are used in the diagnosis and monitoring of many diseases, thanks to biomarkers that can be observed in body fluids. This review covers the recent advances dealing with the design and strategies for the development of LFA for the detection of biomarkers used in clinical applications in the last 5 years. We focus on various strategies such as choosing the nanoparticle type, single or multiple test approaches, and equipment for signal transducing for the detection of the most common biomarkers in different diseases such as cancer, cardiovascular, infectious, and others including Parkinson's and Alzheimer's diseases. We expect that this study will contribute to the different approaches in LFA and pave the way for other clinical applications.