Device Reader of Lateral Flow Tests  Home>>Device Reader of Lateral Flow Tests

Contact Us

Device Reader of Lateral Flow Tests

In case of gold nanoparticles or other color producing labels, qualitative or semi-quantitative analysis can be done by visual inspection of colors at test and control lines. The major advantage of visual inspection is rapid qualitative answer in “Yes” or “NO”. Such quick replies about presence of an analyte in clinical analysis have very high importance. Such tests help doctors to make an immediate decision near the patients in hospitals in situations where test results from central labs cannot be waited for because of huge time consumption. But for quantification, optical strip readers are employed for measurement of the intensity of colors produced at test and control lines of strip. This is achieved by inserting the strips into a strip reader and intensities are recorded simultaneously by imaging softwares. Optical images of the strips can also be recorded with a camera and then processed by using a suitable software. Procedure includes proper placement of strip under the camera and a controlled amount of light is thrown on the areas to be observed. Such systems use monochromatic light and wavelength of light can be adjusted to get a good contrast among test and control lines and background. In order to provide good quantitative and reproducible results, detection system should be sensitive to different intensities of colors. Optical standards can be used to calibrate an optical reader device. Automated systems have advantages over manual imaging and processing in terms of time consumption, interpretation of results and adjustment of variables. By using this image analysis system, the detection limit improved 10-fold compared to visual interpretation. GT 710 Portable Lateral Flow Reader is a portable, ready-to-use, high-reliability, easy-to-use, rapid testing reader which is designed to provide quantitative or qualitative results for colloidal gold immunoassays at the point to need.

In case of fluorescent labels, a fluorescence strip reader is used to record fluorescence intensity of test and control lines. Fluorescence brightness of test line increased with an increase in nitrated ceruloplasmin concentration in human cerum when it was detected with a fluorescence strip reader, such as Creative Diagnostics® fluorescent immunoassay analyzer FIA7100. A photoelectric sensor was also used for detection in LFA where colloidal gold is exposed to light emitting diode and resulting photoelectrons are recorded. Chemiluminescence which results from reaction of enzyme and substrate is measured as a response to amount of target analyte. Magnetic strip readers and electrochemical detectors are also reported as detection systems in LFTS but they are not very common. Selection of detector is mainly determined by the label employed in analysis.

Figure 5-1 Design principles of a detector module for colorimetric or fluorescence measurements A projected light dot is moved across the lateral flow strip. In reflectrometric measurements, the light is reflected back into the reader. At the peaks, less light is reflected due to absorption of the light by the label. Therefore, peaks for reflectrometric (colorimetric) measurements are below the baseline (negative peaks). The label can be of any color as the reader can be configured with various wavelengths

Figure 5-2 Design principles of a detector module for Magnetic strip readers

Before commercialization of any POC device, several aspects of the product are carefully examined. Every lab tested prototype cannot be brought to market without a detailed optimization of assay steps, device material and results read out. Suitability of assay, development of device design, study of consumables and application areas serve as drivers in commercialization of any device. Growing rate of commercial applications of lateral flow assay based devices is very high. It can be safely said that LFA devices are among first commercialized microfluidic based POC products. These devices are being used for qualitative and quantitative analysis for a variety of analytes. All the products including labels, biorecognition molecules, strip readers and a kit of whole set up are being provided by many companies. Lateral flow assay strips are used for the applications in medical, veterinary, and consumer diagnostics, food and beverage testing, environmental and agriculture testing. Market size and opportunities in future have been described in terms of generated revenues and growing demand.

Get in touch