287 articles
Immunologic Tests
Immunologic tests, also called immunodiagnosis or serologic tests, are antibody-antigen-based diagnostic assays, spanning ELISA, radioimmunoassay, agglutination, and lateral flow immunoassay formats used for pregnancy, infection, hormone, and drug detection.
Immunophenotyping
Immunophenotyping is a laboratory assay that identifies and quantifies immune cells by their protein markers, usually via flow cytometry, underpinning leukemia classification, HIV CD4 monitoring, and MRD follow-up.
Immunoturbidimetry
Immunoturbidimetry is a homogeneous immunoassay technique that quantifies analytes such as serum proteins by measuring the turbidity, or loss of transmitted light, from antigen-antibody complexes, and runs on automated clinical chemistry analyzers.
Indirect antiglobulin test
The indirect antiglobulin test (IAT) is a blood-bank laboratory method that detects free antibodies against red cells in serum, underpinning pretransfusion antibody screening, antibody identification, and antenatal testing.
Indirect ELISA
Indirect ELISA is an immunoassay that measures specific antibodies in serum or plasma, using an enzyme-linked secondary antibody for amplification and greater sensitivity than direct ELISA.
Inferior petrosal sinus sampling
Inferior petrosal sinus sampling (IPSS) is an endocrinology procedure that distinguishes pituitary from ectopic ACTH secretion in Cushing syndrome, the gold standard when pituitary MRI is equivocal.
Interferon gamma release assay
The interferon gamma release assay, or IGRA, is a blood test that measures interferon-gamma released by T cells exposed to tuberculosis antigens, detecting infection, mainly latent tuberculosis, without BCG interference.
Intermittently scanned continuous glucose monitoring
Intermittently scanned continuous glucose monitoring (isCGM), also called flash glucose monitoring, is a diabetes monitoring method in which a wearable sensor displays readings only when scanned.
Inulin clearance
Inulin clearance is a renal function test that measures the rate at which the kidneys remove inulin from plasma, long considered the gold standard for measuring glomerular filtration rate.
Invasive glucose monitoring
Invasive glucose monitoring measures blood glucose by sampling body fluid directly, either fingerstick blood on test strips or subcutaneous continuous glucose monitoring (CGM) sensors reading interstitial fluid.
Iohexol clearance
Iohexol clearance is a clinical test that measures kidney function by tracking injected iohexol's disappearance from blood, giving a measured glomerular filtration rate for transplant, donor, and drug-dosing decisions.
Karyotype analysis
Karyotype analysis is a cytogenetic test that examines the number and large-scale structure of chromosomes in dividing cells, diagnosing conditions such as Down syndrome, Turner syndrome, and leukemia-related abnormalities.
Ki-67 immunostaining
Ki-67 immunostaining is a pathology method that measures the fraction of tumor cells in the active cell cycle, reported as a labeling index for grading and prognosis.
Laboratory-developed test
A laboratory-developed test (LDT) is an in vitro diagnostic designed, manufactured, and used within a single CLIA-certified laboratory, common in genetic testing, oncology, and molecular diagnostics.
Latex agglutination
Latex agglutination is a rapid immunoassay in which antibody- or antigen-coated latex beads visibly clump within minutes, detecting antigens or antibodies in over 100 infectious diseases.
Line probe assay
A line probe assay (LPA) is a nucleic acid test that amplifies DNA by multiplex PCR and detects it on a membrane strip, used for tuberculosis drug-resistance testing.
Lipid profile
Lipid profile (lipid panel): blood test measuring total cholesterol, HDL-C, and triglycerides, with calculated LDL-C and non-HDL-C, used for ASCVD risk screening; non-fasting sampling is now standard, with Martin/Hopkins or Sampson equations preferred over Friedewald.
Lipoprotein insulin resistance index
The lipoprotein insulin resistance (LP-IR or LPIR) index is a blood test score, from 0 to 100, that estimates insulin resistance from six NMR-measured lipoprotein parameters.
Liquid biopsy
A liquid biopsy is a minimally invasive diagnostic method that analyzes circulating tumor DNA and cells in blood to detect cancer, guide treatment selection, and monitor recurrence after surgery.
Liquid-based cytology
Liquid-based cytology is a specimen preparation method that suspends cells in preservative fluid and deposits a thin, uniform slide layer, introduced in the 1990s for Pap screening.
Luciferase immunoprecipitation system assay
The luciferase immunoprecipitation system (LIPS) assay is a liquid-phase serological method, published in 2009, that quantifies serum antibodies against a luciferase-tagged antigen without radioisotopes or per-antigen optimization.
Lumbar puncture
Lumbar puncture: needle into the lumbar subarachnoid space (L3–L4/L4–L5) to collect CSF, measure pressure, or give intrathecal drugs; central to meningitis diagnosis, with PCR-first testing and atraumatic needles reducing headache risk.
Luteinizing hormone test
The luteinizing hormone test is a blood or urine measurement of LH, a pituitary hormone, used to time ovulation, assess fertility, and diagnose puberty and pituitary disorders.
Lymphocyte transformation test
The lymphocyte transformation test is an in vitro blood assay measuring lymphocyte proliferation after stimulation with an antigen or suspected drug, used to diagnose delayed drug hypersensitivity.
Mantoux test
Mantoux tuberculin skin test (TST, PPD test): intradermal injection of 0.1 mL purified protein derivative read at 48-72 hours by induration in mm; CDC cut points 5, 10, 15 mm; developed by Mantoux 1908.
Maternal serum screening
Maternal serum screening is a blood test performed during pregnancy that measures fetal and placental proteins to estimate the risk of chromosomal abnormalities and open neural tube defects.
Measurable residual disease detection
Measurable residual disease detection is a set of highly sensitive laboratory assays that count the few malignant cells remaining in bone marrow or blood after treatment.
Medical laboratory
Medical laboratory (clinical laboratory): facility testing human specimens for diagnosis, prevention, and treatment. About 14 billion US tests yearly in 266,000+ CLIA-certified labs; ISO 15189 is the main accreditation standard; most errors are pre-analytical.
Medical laboratory scientist
Medical laboratory scientist (MLS), formerly medical technologist (MT): bachelor's-level US laboratory professional testing blood, urine, and tissue in hematology, chemistry, microbiology, blood bank, and molecular benches; ASCP/AMT/AAB certified, $62,930 median pay, four-state licensure.
Metabolic screening
Metabolic screening is testing of newborn heel-prick blood spots, mostly by tandem mass spectrometry, to detect treatable inborn errors of metabolism such as PKU and MCADD before symptoms appear.