Introductory Concepts Flashcards
Define Reference Interval
lab data results we expect to see in healthy animals
Gaussian Reference Distribution
distribution of reference analytes determined by mean +/- 2SD
central 95% of results of healthy individuals
bell-curve
Non-Gaussian Reference Distribution
distribution of reference analytes has a skewed distribution with enzymes
Population-based Reference Intervals
calculatedd from a population of healthy adult animals of a given species for a given test
est. by each lab
List the order in which samples should be put into blood collection tubes
- citrate (blue top)
- red top
- heparin (green top)
- EDTA (purple top)
- oxalate (grey)
What anticoagulant is in blue top tubes?
citrate
What anticoagulant is in red top tubes?
trick question - none
What anticoagulant is in green top tubes?
heparin
What anticoagulant is in purple top tubes?
EDTA
What anticoagulant is in grey top tubes?
oxalate
What test is run off of blue top tubes?
coagulation tests
What test is run off red top tubes?
chemistry
What test is run off green top tubes?
chemistry
(least interference with chem)
What test is run off purple top tubes?
CBC
(preserves cell morphology)
What test is run off grey top tubes?
glucose
What happens if a citrate tube is contaminated with heparin?
inadequate activation of prothrombin
What happens when a heparin tube is contaminated with EDTA?
increases plasma K+
decreases plasma Ca2+
Qualitative
present or absent
positive or negative
Semiquantitative
approximate concentration
(urine dipstick)
Quantitative
attempt to get a concentration
Analytical Precision
repeatability
Analytical Accuracy
does the assay produce the expected concentration
Analytical Specificity
able to detect analyte of interest when interfering substances are present
Analytical Sensitivity
able to detect differences between concentrations
Detection Limit
lowest detectable concentration
Accuracy
degree of closeness of a measured value to the true value of analyte
Precision
ability of an assay to give similar results if analyzed several times
Reliability
ability of an assay to be accurate and precise
Types of assay errors
preanalytical
analytical
post analytical
Preanalytical Errors
test result only as good as the sample
Analytical Errors
poor analytical properties of the assay
Post Analytical Errors
transcriptional errors
verbal reports translated incorrectly
