quality control - clinical chemistry Flashcards
closeness of the result to the true value
accuracy
the goal of good quality control program
results within narrow, useable and acceptable limits
ensures precision and accuracy of the quantitation in clinical chemistry
quality control
ability of repeated test results to be close to each other; closeness of one test result to another
precision
ability to determine particular substance
specificity
ability to detect and measure the smallest measurement of a substance and used to determine the significant deviation
sensitivity
formula for sensitivity
+/- x 100
to be able to easily repeat the result
practicability
maintain the precision and accuracy of the test results after different variations
reliability
quality control in a certain laboratory to check if day to day performance deviates from the standard
intralaboratory
several laboratories must yield the same test results
interlaboratory
characteristics of serum to be pooled
clear nonhemolyzed nonlipemic nonicteric undyed
examples of commercially prepared control
Versatrol
Labtrol
Enzatrol
Manitrol
examples of non-commercially prepared controls
Fasting human donor
Left over sera
Animal blood
Blood bank plasma (expired)
sum of data divided by total number of data
mean
percentile expression of mean which shows relative magnitude variability
CV
random variation; measures the distribution of range values around the mean
SD
variability and shows significant differences of groups of data
variance
premise the allowable error
tonks formula
causes of trend
deterioration of reagents
changes on the concentration of standard
incomplete protein precipitation
causes of shift
deterioration of standard but constant level
newly made standard but at low concentration
reagent has shifted therefore new level of sensitivity
six or more consecutive control values going up or down the mean
trend
six or more consecutive control values on the same side of the mean; abrupt changes
shift
values are far from the main set of values
outliers
outlier is rejected when
2 or more outliers in 20 days
when to accept outliers
if 1 outlier in 20 days
correction in random error
reassay using the same reagent
causes of random error
mislabeling of sample
mixing of sample and reagent
pipetting errors
temp and voltage fluctuation
types of systematic error
aging phenomenon
personal bias
causes of systematic error
improper calibration deteriorate reagents sample instability (unstable sample) instrument drift changes in standard material
correction of systematic error
prepare new control
restandardize assay
check the wavelength
prepare new reagents
what are clerical errors
wrong punching, calculations
evaluating the reliability of laboratory results
proficiency survey
when DOP does not offer such test for a specimen, this will be sent to Hi-Precision
send-out specimens
abrupt changes in referrals:
changes in the previous result
changes in the normal values (mean becomes increased or decreased)
T/F: always prioritize emergency and icu ward’s specimens first
T
Do not render send-out specimens such as: _______ and _______
ionized calcium and lipase
should you centrifuge serum specimens?
no to avoid hemolysis
who to inform when TDM is requested?
pre-analytic staff for this patient may be taking lithium or valproic acid
if TDM is encountered, what should we take note?
ask for:
time and date of extraction
dosage of drugs
time when was the drug taken
A1 in intern’s designation is responsible for
pre-analytic analysis (bali they ensure if the specimen could be used if not edi reject)
A2 in intern’s designation is responsible for
analytic receptionist
who to inform when troponin I, iron studies and such are requested?
inform the staff on duty
if test request have both send-out request and chemistry request from the lab, who to inform?
staff on duty
B intern is responsible for?
incharge of TAT logging (turn around time)
if missing entries are found in the TAT, who to inform?
staff on duty
C intern is incharge of?
result warderer
when to ask for staff on duty for his/her sign? how about resident on duty?
if results are correct - for staff on duty
if troponin or referrals are already added from the logbooks - resident on duty
Intern E is assigned as:
in the immunology section
T/F: in the morning chemistry staff is available while during the night, immunology staff is available
F since chemistry is available during the night time since immunology staff are only available during day time
principles used by VITROS 5, 1 MACHINE
potentiometric, colorimetric, turbidimetric, immunorate
VITROS 3600 in immunology
enhanced chemiluminescence using microwell technology
