CC

• PRACTICABILITY


  Method is easily repeated
• RELIABILITY


  Maintaining accuracy and precision
• INTRALAB/INTERLAB QC


  Daily monitoring of accuracy and precision
• INTERLAB/EXTERNAL QC


  Proficiency testing (Reference lab)

  Long-term accuracy

  Difference of >2: not in agreement with other lab
• QC MATERIALS


  Available for a minimum of 1 year
• BOVINE CONTROL MATERIALS


  Preferred (Human:biohazard)

  Not for immunochem, dye-binding, and bilirubin
• MATRIX EFFECT


  Improper product manufacturing

  Unpurified analyte

  Altered Protein
• Precision Study


  First step in method evaluation
• SD


  Dispersion of values from the mean
• CV


  Index of precision

  Relative magnitude of variability (%)
• VARIANCE


  Measure of variability

  SD2
• YOUDEN/TWIN PLOT


  Compare results obtained from different lab
• SHEWHART LEVEY-JENNINGS CHART


  Graphic representation of the acceptable limits of variation
• TREND


  Gradual loss of reliability

  Cause: Deterioration of reagents
• SHIFT


  Values: One side or either side of the mean

  Cause: Improper calibration
• KURTOSIS

  Degree of flatness or sharpness
• PRECISION


  Random error
• ACCURACY


  Systemic error
• RANDOM ERROR


  Imprecision; Indeterminate
• CAUSES OF RANDOM ERROR

  • Mislabelling
  • Pipetting error
  • Improper mixing of sample and reagents
  • Voltage/temperature fluctuation
  • Dirty optics
• PARAMETERS OF RANDOM ERROR

  SD, CV
• SYSTEMATIC ERROR


  Inaccuracy; Determinate
• CAUSES OF SYSTEMATIC ERROR

  • Improper calibration
  • Deterioration of reagents
  • Contaminated solution
  • Sample instability/unstable reagent blanks
  • DIminishing lamp power
  • Incorrect sample and reagent volume
• PARAMETERS OF SYSTEMATIC ERROR

  Mean
• TEST METHOD

  Westgard: at least 40 samples
• REFERENCE METHOD

  Westgard: preferably 100 samples
• QUALITY ASSURANCE


  Tripod:

  Program development

  Assessment and monitoring

  Quality improvement
• WAVELENGTH


  Distance between 2 successive peaks (nm)

  Lower frequency = Longer wavelength

  Higher frequency = Shorter wavelength
• SPECTROPHOTOMETRIC MEASUREMENT

  Measure light intensity in a narrower wavelength
• PHOTOMETRIC MEASUREMENT


  Measure light intensity w/o consideration of wavelength

  Multiple wavelength
• LASER


  Light Amplification by Stimulated Emission of Radiation

  Light source for spectrometry
• VISIBLE REGION


  Tungsten light bulb

  Mercury arc
• UV


  Deuterium lamp

  Mercury arc

  Xenon lamp

  Hydrogen lamp
• IR


  Merst glower

  Globar
• STRAY LIGHT


  Wavelength outside the band

  Most common cause of loss of linearity
• NICKEL SULFATE


  Prevents stray light
• CUTOFF FILTER


  Anti-stray light
• ALUMINA SILICA GLASS CUVET

  Most commonly used cuvet
• QUARTZ/ PLASTIC CUVET


  UV
• GALVANOMETER / AMMETER


  Meter or read-out device