287 articles
Clinical chemistry
Clinical chemistry: laboratory-medicine discipline measuring blood and urine analytes for diagnosis; roots in 19th-century medicine; US field organized by AACC/ADLM (founded 1948), whose flagship journal Clinical Chemistry (ISSN 0009-9147) launched 1955.
CO-oximetry
CO-oximetry is a spectrophotometric laboratory method that measures fractions of oxygenated hemoglobin, deoxygenated hemoglobin, carboxyhemoglobin, and methemoglobin in a blood sample, detecting carbon monoxide poisoning and methemoglobinemia.
Companion diagnostic
A companion diagnostic is an in vitro test essential for the safe, effective use of a specific drug, identifying patients likely to benefit or suffer serious adverse reactions.
Comprehensive genomic profiling
Comprehensive genomic profiling (CGP) is an oncology diagnostic using next-generation sequencing to detect many cancer-related alterations in one assay, matching targeted therapies to the tumor's genomic makeup.
Comprehensive metabolic panel
Comprehensive metabolic panel (CMP), also called chem 14 or chemistry panel: a routine blood test measuring 14 substances, including glucose, electrolytes, calcium, proteins, liver enzymes, bilirubin, BUN, and creatinine, to assess metabolism, liver, and kidney health.
Congo red staining
Congo red staining is a histological dye method for detecting amyloid: Congo red binds amyloid fibrils in tissue sections, showing red staining and characteristic birefringence under crossed polarizers.
Contour Next
Contour Next is a family of blood glucose monitoring systems, with meters and test strips made by Ascensia Diabetes Care, introduced in 2012 as the successor to Bayer's CONTOUR meters.
Coombs test
Coombs test, or antiglobulin test (direct DAT, indirect IAT), detects non-agglutinating antibodies against red blood cells using antihuman globulin; described by Coombs, Mourant, and Race in 1945 for Rh antibodies, used in hemolytic anemia, transfusion testing, and hemolytic disease of the newborn.
Counterimmunoelectrophoresis
Counterimmunoelectrophoresis (CIE), also called counter-current immunoelectrophoresis, is a serological technique in which an electric field drives antigen and antibody together in a gel, forming a visible precipitin line.
COVID-19 testing
COVID-19 testing detects infection with SARS-CoV-2, the virus causing COVID-19, using specimens from the nose or mouth. Two main viral tests are used: PCR and rapid antigen tests.
Creatinine clearance
Creatinine clearance (CrCl) is a kidney function test estimating glomerular filtration rate from blood and 24-hour urine creatinine; it overestimates true GFR and has largely been replaced by eGFR equations.
Cross Reactions
Cross Reactions (cross-reactivity): serological reactions where an antiserum against one antigen also reacts with a closely related, non-identical antigen; basis of allergy cross-reactivity, immunoassay interference, and serology false positives.
ctDNA assay
A ctDNA assay is a blood-based diagnostic test that detects circulating tumor DNA released by tumors, used to select therapy, detect molecular residual disease, and monitor relapse.
ctDNA monitoring
CtDNA monitoring is a liquid-biopsy method that repeatedly measures tumor-derived DNA fragments in blood plasma to track tumor burden over time, detecting colorectal cancer recurrence a mean 8.7 months before imaging.
Cytodiagnosis
Cytodiagnosis is the diagnosis of disease by microscopic examination of individual cells, clusters, and tissue fragments from body fluids, scrapings, and fine-needle aspirates, usually confirmed by biopsy.
Cytogenetic analysis
Cytogenetic analysis is a family of laboratory techniques that detect chromosomal abnormalities in cells, used to diagnose genetic disease and blood and solid-tumor cancers, most notably the Philadelphia chromosome in leukemia.
D-dimer
D-dimer (fragment D-dimer, fibrin degradation fragment) is a fibrin degradation product measured in blood to rule out deep vein thrombosis and pulmonary embolism; standard 500 µg/L cutoff, age-adjusted age×10 cutoff, high sensitivity, low specificity.
D3-creatine dilution
D3-creatine dilution (D3Cr) is a stable-isotope test measuring total skeletal muscle mass from one oral dose of deuterated creatine and a urine sample, validated against MRI.
David Zhang
David Yu Zhang is an American bioengineer known for nucleic acid diagnostics and liquid biopsy for cancer; formerly a Rice University professor, he received a PECASE award in 2019.
Diabetes screening
Diabetes screening tests asymptomatic or at-risk people for diabetes and prediabetes using fasting glucose, glucose tolerance, or HbA1c tests, aiming to detect disease before symptoms appear.
Diagnostic Reagent Kits
Diagnostic reagent kits: commercially prepared reagent sets (MeSH D011933) containing all components and literature to perform designated in vitro diagnostic tests, from 1880s dry urine tests and 1960s pregnancy and RAST kits to regulated, validated clinical chemistry, immunoassay, and molecular products.
Digital ELISA
The single-molecule array (Simoa) is a digital ELISA technology commercialized by Quanterix that counts individual enzyme-labeled protein complexes in femtoliter wells, roughly 1,000-fold more sensitive than conventional immunoassays.
Dilution method (antimicrobial susceptibility testing)
The dilution method in antimicrobial susceptibility testing exposes bacteria to serial twofold dilutions of an antibiotic to determine the minimum inhibitory concentration, the lowest level preventing visible growth.
Dipstick test
A dipstick test is a low-cost point-of-care urine test in which a plastic strip bearing chemically treated pads changes color to detect glucose, protein, blood, ketones, nitrite, and other analytes.
Direct agglutination test
The direct agglutination test (DAT) is a serological assay that detects anti-Leishmania antibodies in serum by visible clumping of stained parasites, used mainly to diagnose visceral leishmaniasis.
Direct antiglobulin test
The direct antiglobulin test (DAT) is a blood test detecting antibody or complement proteins bound to red blood cells, used to diagnose immune hemolytic anemia and transfusion reactions.
Direct fluorescent antibody technique
The direct fluorescent antibody (DFA) technique detects specific antigens directly in patient specimens using fluorescently labeled antibodies read under a microscope, giving results in about an hour.
Direct-To-Consumer Screening and Testing
Direct-to-consumer screening and testing (DTC, DTCT) sells laboratory and genetic tests directly to consumers without a clinician intermediary; covers FDA oversight tiers, market growth, evidence gaps, harms, and pricing.
DNA ploidy analysis
DNA ploidy analysis is a cytometric method measuring the DNA content of individual cells by flow or image cytometry to detect aneuploidy in cancers and estimate the S-phase fraction.
Dried blood spot testing
Dried blood spot testing is a clinical method in which a drop of capillary blood is dried on filter paper and analyzed, underpinning newborn screening.