Kap.11 Clinical laboratory FYS 4250 Kap.11 Clinical laboratory instrumentation Analyzing patient specimens -> diagnosis and evaluate effectiveness of therapy Blood, urine, cerebrospinal fluid (CSF) and other fluids Precision and accuracy

Spectrophotometer Ease of measurement, satisfactory accuracy and precision, suitability for automated instruments Substances selectively absorb or emit electromagnetic energy at different wavelengths Typically ultraviolet, visible and near infrared Normally: Have to add reagent to exhibit the desired energy-absorbing characteristics Source Hydrogen (90 % in the IR range) + Tungsten (vaporizes on the glass) Wavelength selectors = filters (absorb) and monocromators (utilize prisms and diffraction gratings =narrow bandwidth)

Flame emission/absorption Differs in three ways: Power source and sample holder combined in flame Measuring emission of light, not absorpion of light Determine concentrations of pure metal only

Fluorometer Based on the fact that molecules emit light in a characteristic spectrum immediately after absorbing radiant energy and being raised to an excited state. Mercury arc lamps Right angle to avoid direct transmission from source to detector Advantage: Greater sensitivity (Four orders of magn compared to spectrophotometric methods) Afew number of substances have the property of fluorescence. Disadvantage: Sensitivity of its determinations to temperature and pH of the sam

Analytic automat ACA Analysea ATP = Analytic test pack

Gas/liquid (GLC) cromatography Stationary phase = solid substance Movable phase = gas or liquids

GLC Initial purification Injector introduce patient sample including solvent Carrier gas = inert carrier gas Coloumns = solid phase (1 m long, diameter less than 7 mm)

GLC printout Important advantages: Speed, small amounts of sample and great sensitivity

Electrophoresis Defined as the movement of a solid phase with respect to a liquid (buffer solution). Buffer -> carry current and keep the pH constant Electrid field -> particles similar in charge, size and shape migrate at similar rates

Serum protein electrophoresis

Coulter counter cell counter Hematology RBC, WBC and plateles Anticoagulants Lyzing agent causes cell membranes of RBC to rupture and release HGB

Impedance- detector for cells And for RBC Resistance of WBC is much greater than the fluid -> voltage pulse is created in the circuit. Averaging Cells with volumes greater than 35.9 fl = RBC

2-dimentional scatterplot of coulter counter data Illuminated by a laser to create the light scatter Cell volume = low frequency impedance

Analysis of microscope- images Automated differential counts Pattern recognition