Laboratories & quality control Flashcards
Quiz 1
What have in house lab increased?
- More prosperous demanding of clients
- User-friendly instruments
- availability of trained technicians
- problems associated w/ diagnostic labs
What is the problem when using manual methods in a in house laboratory ?
- human error
2. Not efficient
what are type of automated counters?
- dry chemistry analyses
- serological test- kits
- cost benefit analysis
what are the benefits for in house labs?
- quick dx
- fresh samples
- avoid packing
- improved client relation
- increase profit ( depending)
what are the benefits for commercial labs?
- expert advice
- reliability of results
- health & safety regulation
- wide range of tests
- Avoid certain cost:
- reagents
- maintenance
- parts replacement
what are the standard operating procedures for laboratory records?
- Procedures for various assays run in lab
2. insert sheets accompanying serological kits
what are the forms the are from the clinicians to lab with client info. & Pt data ?
request form
what are the forms that have results from lab to source of sample with explanatory comments?
Results forms
What ensures that entire process in the laboratory are acceptable quality?
Quality assurance
what are type of quality assurances?
- Pre-analytical
- analytical
- Post analytical
what are the characteristics of test results ?
- accuracy
- precision
- reliability
What is analytical process that tracks the ability of the lab to prove accurate/reliable results ?
Quality control
What are the type of Quality controls?
- reliability of instruments
- reliability of technicians
- reliability of reagents
what are the objectives of the quality control?
- detect errors
- report reliable results
- easy to use
What are the type of laboratory errors ?
- random error
2. systemic error
what type of laboratory error is dealing with temperature abuse for reagents?
random error
what type of laboratory error is dealing with expired reagents & faulty instrument ?
systemic error
Why should control serums be ran?
to maintain precision & accuracy
-performed regularly
Why should inspection of equipment be done regularly ?
- prolongs lifespan of instrument
2. accurate results obtained
What methods are used to detect or quantify the concentration of a chemical substance in a fluid?
- Quantitiative assays
- semi-quantitative assays
- Qualitative assays
what are the fluids that are used for laboratory assays ?
- Blood
- Urine
- Other body fluids
what are the other body fluids that are used in laboratory assay?
- Peritoneal
- Pleural
- CSF
- Joint
what are the characteristics of Quantitative Assays?
- results close to true concentration of substance of fluid
- Na
- Glc - Reported as specific numeric value
what are the characteristics of Semi-Quantitative Assay?
- results are approximate of true concentration of substance in fluid
- report in category scale
How is a semi-quantitative assay characterized in results ?
- degree of turbidity in a urine Sample
- category scale:
- degree of turbidity : +..
- less than or less than
- range
what are the characteristics of Qualitative Assay?
- indicated the presence or absence of substance in sample
- reported as negative or positive
what is the degree of closeness of a measured value to true value of analyte ?
Accuracy
what are the analytical properties of laboratory assay ?
- Accuracy
- Precision
- Reliability
what is the ability of ability of an assay to give similar results if analyzed several times ?
precision
what are type of precisions?
- Magnitude of reproducibility
2. magnitude of repeatability
what is the ability of an assay to be accurate & precise ?
reliability
What are type of diagnostic properties of tests ?
- Sensitivity
2. Specificity
what is sensitivity ?
probability of testing positive if the dz of interest is truly present = TP
what does high sensitivity indicate ?
percentage of diseased animals that are positive in the test & the ability of the test to correctly identify positive animals?
what is sensitivity used for ?
screening for disease
high NPV
what is specificity ?
probability of screening negative if the dz of interest is truly absent = TN
what is specificity test used for ?
confirmatory test
high PPV
What is a positive test the correctly identifies the positive animals by gold standard?
TP
1
What is a negative test that correctly identifies the negative animal by gold standard?
TN
what is a positive test that incorrectly identifies negative animals as being positive for Ab or Ag?
False positive → FN
what is a negative test that incorrectly identifies positive animals as being negative for Ab or Ag?
False negative → FN
What describes how a test performs in the field ?
predictive values = prevalence
what is the positive predictive value (PPV)?
probability that a pt w/ + test results actually has the dz if interest
- strongly suggest presence of dz
what is negative predictive vale (NPV)?
probability that a pt w/ - test results actually doesn’t have the dz of interest
-strongly suggest absence of dz
what is the sensitivity formula ?
TP/TP+FN
what is the specificity formula ?
TN/TN + FP
