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The use of the polymerase chain reaction (PCR) in molecular diagnostics has increased to the point where it is now accepted as the gold standard for detecting nucleic acids in molecular diagnostics, providing exquisite sensitivity and specificity for detection of nucleic acid targets. Real-time monitoring of PCR has simplified and accelerated PCR laboratory procedures and has increased information obtained from specimens including routine quantification and differentiation of amplification products. Clinical diagnostic applications and uses of real-time PCR are growing exponentially, real-time PCR is rapidly replacing traditional PCR. For clinical molecular diagnostics, real-time PCR can be used to measure viral or bacterial loads or evaluate cancer status.

Immunochromatography known as lateral flow immunochromatographic assay(LFA) is a analytical device used to detect the presence of one or more target in a liquid samples. It is ideally suited for point-of-care(POC) use to assess the existence of antibodies or pathogens such as viruses and bacteria, simply and quickly. Often termed a"dipstick"assay, the LFA format can be used for detection of antibody or antigen in a clinical sample. The LFA is particularly effective for diagnostics for global health and meets the World Health Organization's ASSURED criteria for diagnostics for the developing world (Afordable, Sensitive, Specific, User friendly, Reliable and robust, Equipment-free and Deliverable to those who need it). LFA consist of multiple components(sample pad, conjugate pad, membrane, absorbent pad, backing card) and materials, requiring time-consuming device assembly.

Lateral flow tests also known as Immunochromatography(IC) is an antigen-detection method conducted on a nitrocellulose membrane that can be completed in less than 20 min.

IC has been used as an important rapid test for clinical diagnosis, but the IC sensitivity is relatively low. Fluorescence Immunochromatography is an improved IC assay using antibodies conjugated with fluorescent beads(fluorescent immunochromatography, FLIC) for quantitatively detection of virus, bacteria and other factors. Although the FLIC strip must be scanned using a fluorescent reader, the sensitivity is significantly improved over that of conventional IC methods.

Enzyme-linked immunosorbent assay(ELISA) is a labeled immunoassay that is considered the gold standard of immunoassays. This immunological test is very sensitive and is used to detect and quantify substances, including antibodies, antigens, proteins, glycoproteins, and hormones. The detection of these products is accomplished by complexing antibodies and antigens to produce a measurable result. An antibody is a type of protein produced by an individual's immune system. This protein type has specific regions that bind to antigens. Anantigen is a protein that can come from some foreign source and, when bound to an antibody, induces a cascade of events through the body's immune system. This interaction is utilized in ELISA testing and allows for identifying specific protein antibodies and antigens, with only small amounts of a test sample. ELISA has been used as a diagnostic tool in medicine, plant pathology, and biotechnology, as well as a quality control check in various industries.

Chemiluminescent immunoassay(CLIA) is an immunoassay technique where the indicator of the analytic reaction is a luminescent molecule. In general, luminescence is the emission of visible or near-visible radiation which is generated when an electron transitions from an excited state to ground state. The resultant potential energy in the atom gets released in the form of light. In spectrophotometry, luminescence has an advantage over absorbance in that the former is an absolute measure whereas the latter is relative.
Chemiluminescent methods including direct-using luminophore markers or indirect-using enzyme markers. In direct chemiluminescent methods, the luminophore markers used are acridinium and ruthenium esters, while the enzymatic markers used in indirect methods are alkaline phosphatase with adamantyl 1,2-dioxetane aryl phosphate (AMPPD) substrate and horseradish peroxidase with luminol or its derivatives as substrate.
Luminous signalling, with its constant kinetic curve, contributed to the development of relatively uncomplicated automatic CLIA instrumentation. CLIA instruments steadily infiltrated the immunometric assay domain, eventually being used to measure serum concentrations of hormones, drugs, vitamins, tumour markers, infectious disease markers, myocardial damage markers and, finally, autoantibodies.