115 articles
Proximity extension assay
The proximity extension assay (PEA) is a homogeneous immunoassay, introduced in 2011, in which pairs of DNA-linked antibodies quantify thousands of proteins from microliter plasma samples by PCR or sequencing.
Radioallergosorbent Test
Radioallergosorbent test (RAST): the first blood assay for allergen-specific IgE, introduced by Wide, Bennich, and Johansson in 1967 and commercialized as Phadebas RAST in 1974; now replaced by fluorescence enzyme assays but still a colloquial term.
Radioimmunoprecipitation Assay
Radioimmunoprecipitation assay (RIPA, Farr assay): sensitive immunoassay using radiolabeled antigens to detect and quantify specific antibodies in serum or CSF; gold standard for AChR antibodies in myasthenia gravis, limited by radioisotope handling.
Radioisotope Dilution Technique
Radioisotope dilution technique: MeSH-defined method of injecting a known radionuclide quantity into a system and monitoring downstream concentration over time; used for blood volume (51Cr, 131I), cardiac output, and industrial flow measurement.
Radioligand Assay
A radioligand assay is an analytical technique that quantitatively determines receptors or binding proteins in body fluids or tissue using a radioactively labeled binding reagent, including the radioimmunoassay.
Raised antibody titre
Raised antibody titre (抗体滴度增高), ICD-11 MA14.1C, is a lab finding of antibody concentration above the reference range, caused by infection, vaccination, autoimmune disease, or malignancy.
Rapid Diagnostic Tests
Rapid diagnostic tests (RDTs), also called rapid or point-of-care tests, are easy-to-use tests giving results in about 20-30 minutes from blood, urine, saliva, or nasal samples; used for COVID-19, malaria, HIV, strep, and pregnancy.
Reticulocyte Count
Reticulocyte count (retic count) is a blood test measuring immature red blood cells to gauge bone marrow erythropoietic activity; used in anemia workup, with manual microscopy and automated flow cytometry methods and RPI correction.
Rheumatoid factor positive
Rheumatoid factor positive: a blood test result detecting RF, an autoantibody against the Fc region of IgG (Waaler-Rose test). Found in 70–90% of rheumatoid arthritis and Sjögren's, hepatitis C, and 10–25% of healthy elderly; anti-CCP is more specific.
Serum bactericidal assay
Serum bactericidal antibody (SBA) assay, also called hSBA or rSBA by complement source, is an in vitro test measuring antibody- and complement-mediated bacterial killing; the accepted correlate of protection for meningococcal vaccines, with hSBA titer 4 or rSBA titer 8 thresholds.
Skin Window Technique
The Skin Window Technique, also known as the Rebuck Skin Window Technique, is a lab method developed by John W. Rebuck to study cellular migration during immune reactions since 1955.
SOVS-CTG study
SOVS-CTG: self-obtained vaginal swabs for Chlamydia trachomatis and Neisseria gonorrhoeae testing. Pooled sensitivity 92%, specificity 98% versus clinician-collected cervical swabs; WHO-preferred specimen for asymptomatic women.
Specimen Handling
Specimen handling covers collecting, preserving, transporting, and storing clinical specimens so they stay stable for accurate lab results; also called specimen collection, it spans the preanalytical phase where 60-70% of laboratory errors occur, governed by CLSI, ISO 15189, and CLIA rules.
Sperm Count
Sperm count, also called semen analysis, measures the number of sperm in an ejaculate; WHO 6th edition (2021) 5th centile is 16 million/ml concentration, 39 million total, not a fertile-infertile cutoff.
Stimulated Raman scattering histology
Stimulated Raman scattering histology (SRH) is a label-free optical imaging method producing histology-like images of unprocessed surgical tissue, developed for brain tumor diagnosis in the operating room.
Syphilis Serodiagnosis
Syphilis serodiagnosis detects antibodies to Treponema pallidum using nontreponemal (RPR, VDRL) and treponemal tests arranged in traditional or reverse screening algorithms, differing in sensitivity, false positives, and cost.
Tissue embedding
Tissue embedding is the histology step in which fixed tissue is infiltrated with a support medium such as paraffin wax, OCT, or resin so thin sections can be cut for microscopy.
Tissue Preservation
Tissue preservation keeps cells and tissues viable or intact outside the body using hypothermic storage, slow freezing, vitrification, or fixation; clinical organ storage uses 0–4°C solutions, while long-term banking relies on cryopreservation at −80 to −196°C.
Treponema Immobilization Test
The Treponema immobilization test (TPI) is a serologic test for syphilis introduced in 1949, which detects antibody that stops the movement of live Treponema pallidum organisms.
Tumor Stem Cell Assay
Tumor Stem Cell Assay (tumor clonogenic assay, HTCA): soft-agar technique measuring tumor stem cell colony formation to test anticancer drugs in vitro; predicts resistance (~90%) far better than sensitivity (~57-62%).
Two-Dimensional Immunoelectrophoresis
Two-dimensional immunoelectrophoresis, or crossed immunoelectrophoresis (CIE, X-IEP), is a gel-based immunoassay in which proteins separated by first-dimension electrophoresis enter an antibody-containing gel at right angles, forming quantifiable precipitation peaks; described by Ressler in 1960 and refined by Laurell.
Urinary Antibody-Coated Bacteria Test
Urinary antibody-coated bacteria (ACB) test, a 1974 fluorescent antibody technique detecting antibody-coated bacteria in urine sediment to localize urinary tract infection to kidney versus bladder; sensitivity about 83%, specificity about 77%, now rarely used.
Urinary Sediment Analysis
Urinary sediment analysis, also called urine sediment microscopy, is the microscopic and chemical examination of urine sediment for cells, casts, crystals, and bacteria; a MeSH-indexed part of urinalysis used to diagnose kidney and urinary tract disease.
Viral Plaque Assay
Viral plaque assay (plaque assay, PFU assay): cell culture method counting plaques of dead cells to quantify infectious virus in PFU/mL; developed by d'Herelle (1917) and Dulbecco and Vogt (1952); basis of the PRNT.
Virus Inactivation
Virus inactivation: irreversible destruction of viral infectivity by heat, UV or gamma radiation, pH extremes, detergents, solvents, and chemical agents; measured as log reduction and validated under ICH Q5A(R2) and EMA guidelines.