Term
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Definition
| Assumption that the absorbency reading of the spec is an accurate reflection of the amount of chomophore present in the test tube |
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Term
| What does the assumption for a spec check require? |
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Definition
1. Proper blanking to eliminate extraneous sources of absorbance
2. Checking the components to be sure they are working within the acceptable limits
3. Calibrating variables that will effect absorbance reasings. |
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Term
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Definition
| Using a sample blank to zero or calibrate your spectrophotometer |
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Term
| What are the clinical uses of blanks? |
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Definition
| Hemolysis, lipemic samples and icteric samples |
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Term
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Definition
| Hemolysis is the release of hemoglobin and other intracellular components from erythrocytes to the surounding plasma, following damage or disruption of the cell membrane |
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Term
| What are some common causes of in vivo hemolysis |
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Definition
Autoimmune hemolytic anemia
Hemoglobinopathies
Drugs
Severe Infections
DIC
Transfusion Reactions
Heart Valves |
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Term
| What are factors that affect in vitro hemolysis? |
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Definition
Patient's condition/lifestyle
The skill of the person collecting the sample
Local environment (temperature, length of trasnport) |
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Term
| In vivo hemolysis remains the leading cause of what? |
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Definition
| Unsuitable specimens for both outpatient and inpatient samples for routine and stat specimens |
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Term
| Hemolysis generates a consistent trend towards overestimation of |
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Definition
ALT and AST
Creatinine
Creatinine Kinase
Iron
LDH |
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Term
| Hemolysis generates a consistent trend toward underestimation of |
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Definition
Albumin
ALP
Chloride and Sodium
GGT
Glucose |
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Term
| What is a lipemic sample? |
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Definition
|
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Term
| What are causes of lipemia? |
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Definition
Presence of fatty substances in the blood.
Bacterial contamination
A recent meal |
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Term
| What is an icteric sample? |
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Definition
| Bright yellow color blood sample |
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Term
| What are some causes of icteric samples? |
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Definition
Liver disease
Hemolytic disorders |
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Term
| What does a lamp check consist of? |
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Definition
Checking the lamp's intensity.
Select a wavelength where only minimal photons are emitted |
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Term
| What does a monochromator check involve? |
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Definition
| Making sure that the light emitted is the same as the wavelength indicated on the control dial |
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Term
| What does a bandpass check involve? |
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Definition
| Uses a holmium oxide or didymium filter. Two absorption peaks are chosen that differ in wavelength by 1 bandpass. When we scroll through a range of wavelengths two distinct peaks should be apparent on the absorbance readout. |
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Term
| What is a common cause of bandpass error? |
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Definition
Warping of the exit slit or on the surface of the monochromator
Dirt |
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Term
| What does a cuvette check involve? |
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Definition
| Reading absorbance of a colored solution in every cuvette used. Clean, unscratched cuvettes should give the same reading every time. |
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Term
| What does a detector check involve? |
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Definition
| The spectrophotometer is checked for stray light that may be caused by a misplaced cover or crack in the chassis. |
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Term
| What is atomic absorption used for? |
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Definition
| Used to measure concentration by detecting absorption of electromagnetic radiation by atoms rather than molecules. |
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Term
| What is the light source used in atomic absorption? |
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Definition
Hollow Cathode Lamp
Evacuated gas tight chamber, anode or inert gas (helium or argon) cathode |
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Term
| How does atomic absorption work? |
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Definition
| Voltage is applied and the filler gas becomes ionized. Ions cause atoms to become excited and the atoms release light energy as they return to ground state |
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Term
| How is the monochromator used in atomic absorption? |
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Definition
| It is used to isolate the desired emission line from the other emission lines |
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Term
| What type of photodetector is used in atomic absorption? |
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Definition
|
|
Term
| What is flame photometry used for? |
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Definition
| It is used to measure the presence of Na+, K+, Mg and Li in a patient's sample |
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Term
| How does flame photometry work? |
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Definition
| Flame photometry uses a solution containing metal ions that isd sprayed into a flame. The ions are energized to emit a light of a characteristic color. |
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Term
| What color is the flame for Li? |
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Definition
|
|
Term
| What color is the flame for Na+? |
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Definition
|
|
Term
| What color is the flame for K+? |
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Definition
|
|
Term
| What color is the flame for Mg? |
|
Definition
|
|
Term
| What type of light source is used in flame photometry? |
|
Definition
|
|
Term
| What type of monochromator is used in flame photometry? |
|
Definition
|
|
Term
| What type of photodetector is used in flame photometry? |
|
Definition
Phototube
Photomultiplier tube |
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|
Term
| What is atomic absorption used for? |
|
Definition
| It is used to analyze metals in body fluids such as blood and urine |
|
|
Term
| What us flame photometry used for? |
|
Definition
| It is used to measure Na+,K+, Mg and Li |
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|
Term
| What is fluorometry used for? |
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Definition
| It is used to mesaure bilirubin and quinine. |
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Term
| How does fluorometry work? |
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Definition
| UV radiation is used on substances that absorb the radiation and become excited. After excitation, they return to ground state and emit fluorescent light |
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Term
|
Definition
| It is the difference (in wavelength or frequency units) between positions of the band maxima of the absorption and emission spectra. Stokes Shift is also observed when the emitted photon has less energy than the absorbed photon. |
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Term
| What type of light source is used in fluorometry? |
|
Definition
| Gas discharge lamp (mercury and xenon) |
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|
Term
| What must the cuvette be made out of in fluorometry? |
|
Definition
| Quartz because they transparent to UV wavelengths of light |
|
|
Term
| What types of monochromators are used in fluorometry? |
|
Definition
|
|
Term
| What type of photodetector is used in fluorometry? |
|
Definition
|
|
Term
| What are some variables that affect the results of fluorometry? |
|
Definition
|
|
Term
|
Definition
| More sensitive and specific than conventional spectrophotometry |
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|
Term
| Disadvantage of fluorometry |
|
Definition
| Sensitive to environmental changes (pH, temperature) |
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Term
| What is nephelometry used for? |
|
Definition
| It is used to detect scattered light bouncing off antigen/antibody complexes |
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Term
|
Definition
| The binding of a specific antibody to its specific antigen |
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Term
|
Definition
| Measures turbidimetry or cloudiness of a solution by measuring the amount of light passing through the solution. |
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Term
| When soluble antigen and antibody join in sufficient amounts and precipitate what results? |
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Definition
|
|
Term
| What type of scattering is predominant in nephelometry? |
|
Definition
|
|
Term
|
Definition
| Largest particles and produces a forward scatter. |
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Term
| What are the uses of nephelometry? |
|
Definition
Urine dipstick readers
Glucometers |
|
|
Term
| What is the law of reflection? |
|
Definition
| The law of reflection states that the angle of incidence equals the angle of reflection. Light gets reflected from a surface at the angle it hits it |
|
|
Term
| What is chemiluminescence? |
|
Definition
| Light produced by chemical reactions that release energy in the form of light |
|
|
Term
| How does chemiluminescence differ from fluorescence? |
|
Definition
| It differs by the excitation produced comes from a chemical reaction, not absorbance of a wavelength of light. |
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Term
|
Definition
| A test that uses antibody and antigen complexes as a means of generating a measurable result |
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|
Term
| What is another name for an antibody:antigen complex? |
|
Definition
|
|
Term
|
Definition
| An immune response that causes the body to generate antibodies |
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Term
|
Definition
|
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Term
|
Definition
| A protein that is produced by the body in response to an "invading" (foreign) substance |
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Term
| When performing an immunoassay if there are antibodies present what does it mean? |
|
Definition
| It means that the antibodies were produced in order to protect against a virus, medication or drug that is being measured for. |
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Term
|
Definition
| Anything measured by a laboratory test. |
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Term
| Immunoassays utilize one or more select antibodies to detect what? |
|
Definition
|
|
Term
|
Definition
| Each site on an antigen that can bind antobodies |
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|
Term
| Antibodies possess high what for a specific antigen? |
|
Definition
|
|
Term
| Antibodies are a type of protein called what? |
|
Definition
|
|
Term
| IgG is a protein composed of what two main structural and functional regions? |
|
Definition
|
|
Term
|
Definition
| Contains the antigen (Ag) binding site the varies between different antibodies |
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Term
|
Definition
| Region of constant structure with an antibody class |
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