Principles of Chemistry Instrumentation Flashcards
(40 cards)
Benefits of Instrumentation
- shortened analysis time
- shortened turnaround time
- higher productivity
shortened turnaround time(TAT)
the time elapsed between ordering a lab test and the physician receiving the result
When Choosing an instrument it is important to consider…
- quality of test results
- test volume
- cost per test
- ease of operation
- maintenance costs
- preventative measurements
- comparison of methods
- integration into LIS
Types of hazards in the lab
biological hazards, physical hazards, chemical hazards
Quality assessment programs used on instruments
- document personnel training
- maintenance and repair logs
- calibrators and controls
- use manufacturer’s protocol
- instrument checks
Instrumentation Principles
- Photometry/spectrophotometry
- reflectance photometry
- nephelometry/turbidity
- ion-selective electrodes
- electrochemical technology
photometer
an instrument that measures the light reflected from a colored reaction product. Use filter. measures the intensity of light.
spectrophotometer
an instrument that measures intensities of light at selected wavelengths. use prism
monochromator
a device that isolates a narrow portion of the light
Light Transmitted (%T)
the percentage of light that passes through a solution reflectance
Light absorbed (%A)
a logarithmic expression of the amount of light absorbed by a substance containing colored molecule; optical density (O.D.)
note* the more concentrated the solution, more is absorbed and less is transmitted
Beer’s law
a mathematical relationship that demonstrates the linear relationship of concentration to absorbance and that forms the basis for spectrophotometric analysis
main difference between photometers and spectrophotometers?
photometers use filters and spectrophotometers uses prism.
note- spectrophotometer is more accurate than the use of filters
Reflectance photometry
measure reflected light; light reflected by colored product.
note* used for hemoglobin
solid-phase chemistry
an analytical method in which the sample is added to a strip or slide containing all reagents for the procedure in dried form
nephelometry/turbidity
- light scatter
- particles in suspension
ion-selective electrodes
an electrode manufactured to detect a specify ion and measure its concentration
- analyzers use two electrodes
- measure electrical potential across membrane
- two electrodes used one known and one unknown
note*- sodium chloride, potassium, bicarbonate
amperometry
the technology that uses electrodes and electrode potential to measure electron generation
- measure generation of electrons
- electrochemical technology
- Accu-chek can be used for sugar, HBAIC, HDL, total cholesterol
Point-of-care testing
- bring test to patient
- small, portable analyzers
- home glucose meters first POC tests
- over-the-counter pregnancy tests
- used everywhere
Where do we use POCT?
in the hospital, bedside in patient room, emergency department, critical care units, surgery
nonhospital sites, screening programs, health fairs, nursing homes, POLs
Components of POCT program
- compliance with regulations
- safety program
- quality assessment
- personnel training and assessment
- technical support
- data management
Advantages of POCT
- rapid results
- patient participation
- less trauma
- reduced errors
- multiskilled personnel
- improved communication
disadvantages of POCT
- increased costs
- risk of:
- personnel training deficiencies
- inadequate quality assessment procedures
- inadequate supervision
Glucose
major carbohydrate in blood, also the major source of energy for the body’s cells
-blood glucose is the most frequently performed clinical test
