287 articles
Georges-Fernand Widal
Georges-Fernand Widal (1862–1929) was a French physician and bacteriologist at Hôpital Cochin in Paris who introduced the typhoid agglutination test in 1896 and helped immunize the French army against typhoid.
Glucose testing
Glucose testing is the clinical measurement of glucose concentration in blood or other body fluids, used to screen for, diagnose, and monitor diabetes and other disorders of glucose metabolism.
Gross examination
Gross examination, or grossing, is the bare-eye inspection, description, measurement, and sampling of surgical specimens in a pathology laboratory before microscopic processing, so the right tissue reaches the histologist.
Guaiac-based fecal occult blood test
The guaiac-based fecal occult blood test (gFOBT) is a chemical stool test that detects heme from bleeding anywhere in the gastrointestinal tract, used for colorectal cancer screening.
Hair analysis
Hair analysis is the laboratory measurement of substances incorporated in the hair shaft to assess drug use, nutrition, or exposure over past weeks to months, unlike blood or urine.
Ham test
The Ham test, also called the acidified serum lysis test, is a hematology assay for paroxysmal nocturnal hemoglobinuria, developed by Thomas Hale Ham in 1939.
Hemagglutination
Hemagglutination is the clumping of red blood cells by antibodies, lectins, or viral proteins such as influenza hemagglutinin binding sialic acid; it underlies blood typing and the hemagglutination inhibition assay used for influenza serology.
Hemagglutination inhibition assay
The hemagglutination inhibition assay (HAI) is a serological test that quantifies antibodies blocking virus-induced clumping of red blood cells, and is the primary method for measuring influenza antibody responses.
Hemagglutination Tests
Hemagglutination tests (HA, HI/HAI, Hirst test) detect and quantify viruses or antibodies by visible clumping of red blood cells via viral hemagglutinin; used for influenza diagnosis, vaccine antigenic characterization, and blood group typing.
Hepatitis serology
Hepatitis serology is blood-based testing for hepatitis virus antigens and antibodies, used to diagnose infection, stage it as acute or chronic, and establish immunity, complemented by nucleic acid testing.
Hepatocellular ballooning
Hepatocellular ballooning is a liver biopsy finding in which injured hepatocytes become markedly swollen with rarefied cytoplasm from keratin 8/18 cytoskeleton collapse, a required feature for diagnosing steatohepatitis.
HER2 testing
HER2 testing is the laboratory measurement of HER2 protein overexpression or ERBB2 gene amplification in tumors, using immunohistochemistry and in situ hybridization, to guide anti-HER2 therapy.
HER2/CEP17 FISH ratio assay
The HER2/CEP17 FISH ratio assay is a dual-probe fluorescence in situ hybridization test measuring HER2 gene signals against chromosome 17 signals to determine breast cancer eligibility for anti-HER2 therapy.
High-resolution melt analysis
High-resolution melt analysis (HRM, also HRMA) is a closed-tube real-time PCR method that detects DNA variants, genotypes SNPs, and estimates methylation without sequencing or labeled probes.
HIV test
An HIV test is a medical diagnostic test that detects HIV infection by measuring HIV-specific antibodies, the viral p24 antigen, or viral RNA in blood, serum, plasma, or oral fluid.
HIV viral load measurement
HIV viral load measurement is a nucleic acid amplification test that quantifies HIV RNA in blood plasma, reported in copies per milliliter, to guide antiretroviral therapy and monitor treatment response.
Homeostatic model assessment
Homeostatic model assessment (HOMA) is a mathematical method that estimates insulin resistance and beta-cell function from a single fasting blood sample, widely used in diabetes research since 1985.
HPV self-collection
HPV self-collection is a cervical cancer screening method in which a person collects their own vaginal sample, tested for 14 high-risk HPV types as primary screening.
HPV self-sampling
HPV self-sampling is a cervical cancer screening method in which a person collects their own vaginal specimen for high-risk HPV DNA testing, raising participation among people who decline clinician-collected sampling.
HPV testing
HPV testing, also known as the HPV DNA test, detects high-risk human papillomavirus DNA or mRNA in cervical or vaginal samples to screen for cervical cancer, the WHO-recommended primary screening method.
Human papillomavirus testing
Human papillomavirus testing is a nucleic acid-based diagnostic method detecting high-risk HPV DNA or mRNA in cervical samples, used since 2020 as the primary cervical cancer screening method in many settings.
Hydrogen breath test
The hydrogen breath test is a non-invasive diagnostic procedure measuring hydrogen and methane in exhaled air after a sugar substrate, detecting carbohydrate malabsorption or small intestinal bacterial overgrowth.
Hypocalciuria
Hypocalciuria (low urinary calcium; ICD-11 MF98.3), also called low urine calcium. Key causes: familial hypocalciuric hypercalcemia (CASR, GNA11, AP2S1 mutations), thiazides, lithium, vitamin D deficiency; CCCR <0.01 suggests FHH over primary hyperparathyroidism.
Hypokaluria
Hypokaluria, also spelled hypokaliuria, is a decreased concentration of potassium in the urine, measured in 24-hour collections to tell renal potassium wasting apart from poor intake or gastrointestinal loss.
Hypophosphaturia
Hypophosphaturia (低リン酸尿症), ICD-11 MF98.6, is abnormally low urinary phosphate, a lab finding distinct from hypophosphatemia; it indicates nonrenal causes such as poor absorption or cellular shift rather than renal phosphate wasting.
IgG index
The IgG index is a CSF and serum ratio used in neurology to detect IgG produced within the central nervous system, once used in multiple sclerosis workup.
IgM antibody-capture ELISA
The IgM antibody-capture ELISA (MAC-ELISA) is a serologic immunoassay that first captures all of a patient's IgM antibodies, then detects virus-specific IgM among them, giving presumptive evidence of recent infection from one sample.
Immunochromatography
Immunochromatography is a rapid assay in which a sample migrates along a chromatographic strip by capillary action, generating a visible signal; it underlies home pregnancy tests and point-of-care diagnostics.
Immunofixation electrophoresis
Immunofixation electrophoresis (IFE) is a clinical lab technique that identifies and types monoclonal immunoglobulins in serum, urine, or CSF, the IMWG gold standard for confirming monoclonal proteins.
Immunologic Pregnancy Tests
Immunologic pregnancy tests detect hCG in urine or serum using antigen-antibody reactions, beginning with the 1960 Wide-Gemzell hemagglutination inhibition test and evolving through RIA, latex agglutination, and enzyme immunoassay into modern home tests.