This category covers the lab methods used to find, identify, and count asbestos fibers in air, dust, and tissue. If a case turns on whether fibers were present and how many, it usually comes down to work done under a microscope. These are the techniques that turn a sample into evidence.
Different methods answer different questions. Polarized Light Microscopy (PLM) identifies asbestos in bulk material like insulation or floor tile. Phase Contrast Microscopy (PCM), the basis of NIOSH Method 7400, counts fibers on an air filter using a Walton-Beckett graticule, a measured grid in the eyepiece. When fibers are too small to see this way, Transmission Electron Microscopy (TEM) and energy dispersive spectroscopy confirm both shape and chemistry. Tissue digestion studies dissolve lung tissue to recover and count the fibers left behind.
You'll also find entries on air sampling, fiber counting rules, detection limits, and the lab-to-lab variability that can make two reports disagree. Every term below links to a full plain-language definition.
Terms in this category
- A549 CellsA549 cells are a line of human lung cells originally taken from a patient's lung adenocarcinoma (a type of lu…
- Abbe Diffraction LimitThe Abbe diffraction limit is a fundamental physical rule that sets the smallest distance at which a traditio…
- Acetone VaporAcetone vapor is the gaseous form of acetone, a common organic solvent, used in laboratory preparation of air…
- Acid DigestionAcid digestion is a laboratory technique that dissolves lung or other tissue using strong chemicals, leaving …
- AHERA TEM MethodThe AHERA TEM method is the transmission electron microscopy procedure EPA requires for clearance air testing…
- Air SamplingAir sampling (also called air monitoring) is the process of collecting samples of air and analyzing them in a…
- Analytical SensitivityAnalytical sensitivity is the asbestos concentration that one counted fiber or structure would represent in a…
- Analytical Transmission Electron Microscopy (ATEM)Analytical Transmission Electron Microscopy is a laboratory technique that uses a high-powered electron beam …
- Annular RingAn annular ring is a ring-shaped feature seen on imaging or in cross-section, where a band surrounds a centra…
- Asbestos FractionThe asbestos fraction is the portion of a bulk material (such as talc, vermiculite, or industrial ore) that c…
- ASTM D5755ASTM D5755 is a standard laboratory method for measuring asbestos in settled dust. Dust is collected from a s…
- ASTM D6281ASTM D6281 is a standardized laboratory method for identifying and counting airborne asbestos fibers collecte…
- ASTM D6480ASTM D6480 is a standard method for measuring asbestos on surfaces by wiping a measured area with a moistened…
- B-ReadA B-Read is a standardized interpretation of a chest X-ray performed by a physician specially certified to cl…
- Becke LineThe Becke line is a thin bright halo that appears at the edge of a particle under a light microscope when the…
- BET nitrogen adsorptionBET nitrogen adsorption is a laboratory method that measures the total surface area of a powder or fiber samp…
- birefringenceBirefringence is an optical property of certain crystals and fibers in which light entering the material is s…
- Bulk Sample AnalysisBulk sample analysis is the laboratory testing of a physical piece of material, such as insulation, floor til…
- CARB Method 435CARB Method 435 is the California Air Resources Board's laboratory method for measuring asbestos in serpentin…
- Carbon Film TEM GridA carbon film TEM grid is a small metal mesh disc (usually about 3 millimeters across) coated with an ultra-t…
- Chatfield EMPs"Chatfield EMPs" refers to the counting and identification rules for elongate mineral particles proposed by m…
- Comet AssayThe comet assay (also called single-cell gel electrophoresis) is a laboratory test that measures DNA damage i…
- Countable FiberA countable fiber is an airborne particle that meets specific size rules used in regulatory air-sampling meth…
- Crossed PolarsCrossed polars is a setup on a polarized light microscope in which two polarizing filters are oriented at 90 …
- Crystallographic AnalysisCrystallographic analysis is a group of laboratory methods that determine how atoms are arranged inside a sol…
- de Broglie WavelengthThe de Broglie wavelength is the wavelength associated with a moving particle, calculated as Planck's constan…
- Diastase-Periodic Acid Schiff (PAS) MethodA two-step histology stain in which tissue is first treated with the enzyme diastase to digest away glycogen,…
- Direct-Transfer MethodThe direct-transfer method is a laboratory technique used to prepare airborne dust samples for analysis under…
- dispersion stainingDispersion staining is an optical microscopy technique used to identify asbestos fibers and other minerals by…
- Electron Backscatter Diffraction (EBSD)Electron Backscatter Diffraction is a technique used inside a scanning electron microscope that identifies a …
- electron energy loss spectroscopy (EELS)Electron Energy Loss Spectroscopy is a laboratory technique used inside a transmission electron microscope to…
- Electron Microprobe AnalysisElectron microprobe analysis is a laboratory method that identifies the chemical elements in a tiny sample by…
- Elemental AnalysisElemental analysis is a group of laboratory techniques that measure which chemical elements (such as magnesiu…
- energy dispersive X-ray spectroscopy (EDS)Energy Dispersive X-ray Spectroscopy is a laboratory technique paired with an electron microscope that identi…
- EPA Method 600/R-93/116EPA Method 600/R-93/116 is a U.S. Environmental Protection Agency analytical procedure for identifying and qu…
- extinction angleThe extinction angle is the angle through which a mineral fiber or crystal must be rotated under a polarized-…
- Fe K-edge XANESFe K-edge XANES (X-ray Absorption Near-Edge Structure spectroscopy at the iron K absorption edge) is an analy…
- Fiber CountingFiber counting is a laboratory method for measuring how many asbestos fibers are in a sample of air, usually …
- Fiber IdentificationFiber identification is the laboratory process of determining whether fibers in a sample are asbestos and, if…
- FiberizingFiberizing is the industrial process of breaking raw asbestos rock into the loose, fluffy individual fibers t…
- Goniometric MeasurementGoniometric measurement is the use of a goniometer, an instrument that measures angles, to determine the prec…
- Gravimetric ReductionGravimetric reduction is a lab preparation that removes most of a sample's binder or matrix before it is exam…
- Hammer-Mill FiberizingHammer-mill fiberizing is an industrial process in which raw asbestos ore or fibrous mineral chunks are crush…
- HistologyHistology is the study of tissues under a microscope. A pathologist examines thin, stained slices of tissue, …
- HRTEMHRTEM stands for High-Resolution Transmission Electron Microscopy, a powerful imaging technique that uses a f…
- Indirect-Transfer MethodThe indirect-transfer method is a laboratory preparation technique used in transmission electron microscopy (…
- Infrared Spectroscopy (IR)Infrared spectroscopy is a laboratory technique that identifies materials by shining infrared light through o…
- Inter-Laboratory VariabilityInter-laboratory variability refers to differences in test results when the same sample, or similar samples, …
- Iron Stain (Prussian Blue)The iron stain, also called Prussian blue or Perls' stain, turns iron in tissue bright blue. Because asbestos…
- ISO 10312ISO 10312 is an international laboratory standard that describes how to count and identify asbestos fibers in…
- ISO 13794ISO 13794 is an international standard that specifies a method for measuring asbestos fibers in ambient (outd…
- ISO 22262ISO 22262 is an international standard, published in several parts, for sampling and analyzing asbestos in co…
- Lattice FringeA lattice fringe is the pattern of parallel lines seen in a high-resolution transmission electron microscope …
- Low-Temperature AshingLow-temperature ashing is a laboratory technique that uses a stream of chemically reactive oxygen plasma to s…
- Membrane Filter MethodThe membrane filter method measures airborne asbestos by pumping air through a thin filter, making the filter…
- MeT-5A CellsMeT-5A is a laboratory cell line of human mesothelial cells, the same type of cells that line the chest and a…
- Microvacuum SamplingMicrovacuum sampling is a way of collecting settled dust from a measured area of a surface by drawing it thro…
- Midget ImpingerThe midget impinger was the standard instrument for measuring workplace dust from the 1930s into the 1960s. I…
- Mixed Cellulose Ester FilterA mixed cellulose ester (MCE) filter is a thin, porous membrane made from a blend of cellulose acetate and ce…
- NIOSH 7402NIOSH 7402 is a standardized laboratory method published by the U.S. National Institute for Occupational Safe…
- NIOSH Method 7400NIOSH Method 7400 is a standardized laboratory procedure for counting airborne fibers collected on a filter, …
- NIOSH Method 7400 Method ANIOSH Method 7400 Method A is a standardized procedure for counting airborne fibers in workplace air samples …
- NIOSH Method 7400 Method BNIOSH Method 7400 is a standardized procedure for counting airborne fibers using phase contrast microscopy (P…
- NIOSH Method 9002NIOSH Method 9002 is the National Institute for Occupational Safety and Health's method for identifying asbes…
- Paraffin BlockA paraffin block is a small block of wax holding a piece of tissue removed during a biopsy, surgery or autops…
- phase contrast microscopy (PCM)Phase contrast microscopy is a light-microscope technique that makes transparent fibers visible by converting…
- Phase PlateA phase plate is a small optical component inserted into the light path of a phase-contrast microscope that s…
- pleochroismPleochroism is an optical property of certain crystals that causes them to appear different colors when viewe…
- PLM Detection LimitThe PLM (Polarized Light Microscopy) detection limit is the smallest concentration of asbestos that can relia…
- Point CountingPoint counting is a way of measuring how much asbestos is in a bulk sample under a polarized light microscope…
- Polarized Light Microscopy (PLM)Polarized Light Microscopy is a laboratory technique that identifies asbestos by passing polarized light thro…
- Postmortem ArtifactA postmortem artifact is a change in tissue, cells, or sampled material that occurs after death (or during au…
- Provenance AnalysisProvenance analysis is the scientific work of tracing asbestos fibers back to the geological deposit or comme…
- QAMA Quebec Standard TestThe QAMA (Quebec Asbestos Mining Association) Quebec Standard Test was an industry method for measuring airbo…
- Quantitative Uncertainty BoundsQuantitative uncertainty bounds are the numerical range (usually expressed as a confidence interval, error ba…
- Quebec Standard TestThe Quebec Standard Test was a mid-20th-century air-sampling method developed in the Quebec chrysotile mining…
- Quebec Standard Testing MachineThe Quebec Standard Testing Machine was a mechanical device developed in the Quebec chrysotile asbestos indus…
- Retention TImeRetention time is how long a particular substance takes to travel through an analytical instrument's separati…
- Rigden methodThe Rigden method is a laboratory technique for measuring the specific surface area of fine powders by determ…
- Scanning Electron Microscopy (SEM)Scanning Electron Microscopy is a laboratory imaging technique that uses a focused beam of electrons, rather …
- Selected Area Electron Diffraction (SAED)Selected Area Electron Diffraction is a technique used inside a transmission electron microscope to identify …
- Settled DustSettled dust is dust that has fallen out of the air and collected on floors, ledges, furniture, clothing or e…
- Sign of ElongationThe sign of elongation is an optical property of a fiber seen under a polarized light microscope with a compe…
- Simulated Body FluidSimulated body fluid (SBF) is a laboratory solution formulated to mimic the chemistry of human extracellular …
- Sodium Hypochlorite DigestionSodium hypochlorite digestion is a laboratory technique that uses concentrated bleach to dissolve lung or oth…
- Stanton-style Intrapleural ChallengeA laboratory experiment in which fibers (asbestos or other mineral fibers) are surgically implanted directly …
- STEMSTEM stands for Scanning Transmission Electron Microscope (or Microscopy), a high-powered imaging technique t…
- Structure CountingStructure counting is the laboratory practice of identifying and tallying individual asbestos "structures" (f…
- Suzuki EMPsSuzuki EMPs refers to electron microprobe and electron microscopy protocols developed by Dr. Yasunosuke Suzuk…
- Synchrotron X-ray MicroscopySynchrotron X-ray microscopy is a high-resolution imaging technique that uses the intensely bright X-rays pro…
- TEM/EDSTEM/EDS stands for Transmission Electron Microscopy combined with Energy-Dispersive X-ray Spectroscopy. It is…
- Thermal PrecipitatorA thermal precipitator is a dust-sampling instrument that draws air slowly past a heated wire. The heat pushe…
- Thermogravimetric AnalysisThermogravimetric analysis (TGA) is a laboratory method that measures how a material's weight changes as it's…
- Tissue DigestionTissue digestion is a laboratory technique in which a small sample of lung or other tissue is chemically diss…
- Transmission Electron Microscopy (TEM)Transmission Electron Microscopy is a laboratory technique that passes a beam of electrons through an extreme…
- TriacetinTriacetin (glycerol triacetate) is a clear, odorless liquid ester of glycerin and acetic acid. In the cigaret…
- Visual Area EstimationVisual area estimation is the way most labs report how much asbestos is in a bulk sample: the analyst looks a…
- Walton-Beckett graticuleThe Walton-Beckett graticule is a small circular grid etched onto a glass disk that fits inside the eyepiece …
- WHO Counting ConventionThe WHO Counting Convention is a standardized rule, established by the World Health Organization, for decidin…
- Wipe SamplingWipe sampling collects settled dust by wiping a measured area of a surface with a moistened wipe, which is th…
- Work Practice SimulationA work practice simulation is a study in which people reproduce a task, such as sanding joint compound, cutti…
- X-Ray Diffraction (XRD)X-Ray Diffraction is a laboratory technique that identifies minerals by measuring how X-rays bounce off the r…
Terms in this category
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