1010 unit 3 Flashcards
what is a control?
represents a specimen with a known value that is similar in compositions to the patients sample
describe random errors
errors that affect the reproductivity of a test system. associated with 1-32, R-4s, and outliers
what is sensitivity?
defined as the proportion of cases with a specific disease that gives a positive test result. those results are truly positive
what is an analyte
substance or constituent being measured
how do you develop a reference range?
1) at least 30 healthy people are tested
2) test results are averaged to create a mean
3) calculate SD
4) calculate both the +/- 2SD
5) calculate the range using -/+ 2SD from the mean
what is osmolarity formula?
osmoles of solute per liter of solution
what is quality assurance/assessment
comprehensive set of policies, procedures, and practices that ensure the laboratories results are accurate and reliable. Includes record keeping. calibration and maintenance of equipment. QC, proficiency testing and training
what is specificity?
defined as the proportion of cases with the absence of the specific disease that gives a negative test result. Those tests are truly negative
what is the warning rule where 1 control value outside +/- 2SD?
1-2s
what is proficiency testing?
program where samples are sent to a group of labs to analysis. The results are then compared with the other labs. A mean by which quality control between laboratories is maintained
what are reference values?
“normal values”, the laboratory must provide reference values for the physician so that they know what is considered normal for that assay
what is standard deviation?
statistical term for the mathematical expression of a guassian curve. Measures the scatter of dat around the mean of a guassian distribution
what is mean?
average of set of numbers
what are standards?
highly purified substances of a known composition. used to calibrate and measure accuracy
what is median?
middle value of body of data
10x
rejection rule, 10 consecutive points are all above or below the mean
what is the rejection rule for 2 consecutive control values outside of -/+ 2SD
2-2s
what is the rejection rule for 1 control value outside of -/+ 1 SD?
1-3s
what is mode?
value that occurs most commonly in the mass of data
what are systemic errors?
–errors that affect the accuracy or closeness to true value. Causes bias in a single direction only.
–associated with 1-3s, 2-2s, 41-s, 10x, shifts, trends or calibration failure
what is CV%?
(SD/mean) x 100 = CV%
–helpful is comparing precision differences among assays and methods
what is calibration?
comparison of the measurements of an instrument or glassware to a known physical constant
what is a trend?
four consecutive control values moving in one direction
what is a shift?
four consecutive control values all above or below the mean
what are some sources of systemic errors
–worn pump tubing
–decreased bulb output
–improperly calibrated pipettor
how often is a control value expected to fall outside of 2SD?
1 in 20 runs
what are characteristics of controls in the lab?
1) similar to composition to unknow specimen
2) has known concentration
3) is included in every batch or run
4)must be treated in the exact same way as the patient specimen
5) reuslts must fall within the set of QC results to report patient results
what is “out of control”
a problem observed determining that patients results cannot be reported
what are some sources of random errors?
–worn pump tubing
–varying bulb output
–technique
-unstable reagent,
–unstable environment
68% of all values in a measured group fall within this area
1SD
what is the rejection rule that is 1 control value exceeds the mean +2SD and 1 control value exceeds -2SD?
R-4s
99.7% of all the values in a measure group fall within this area
3SD
95% of all values in a measured group fall within this area
2SD
what to do for troubleshooting Out of Control QC
follow the manufacturer’s troubleshooting procedure specified for the test procedure - may include ——-
–evaluation of type of expiration dates and calibration dates
–evaluation of type or error; systemic or random
–evaluating recent events
–preparing a new control material
quality management consist of what?
–quality assurance
–quality control
In addition to blood and urine, what are the major types of body fluid specimens that can be tested by clinical laboratory?
–synovial fluid
–cerebrospinal fluid
– peritoneal fluids
–pericardial fluid
–sweat
–seminal fluid
The CLIA ‘88 amendment regulations established minimum requirements with general QC systems for what?
all nonwaived testing
the abbreviation TJC stands for an organization that does what ?
accredits hospitals and inspects clinical laboratories
the abbreviation CAP stands for an organization that does what?
accredits only hospital laboratories only
the abbreviation for COLA stands for an organization that does what?
accredits physicians offices
the abbreviation for CLIA stands for an organization that does what?
determines minimum QC requirements for nonwaived assays
ISO 15189 is intended for what use?
medical laboratories
six sigma management focuses on what?
reduction of variability in laboratory results
what does CLIA ‘88 require?
participation in proficiency testing
if the incorrect anticoagulant is in a blood collection tube, it is a what?
an active error
incorrect identification of a patient is what kind of error?
preanalytical error
malfunction of a microprocessor that affects accuracy in testing is what kind of error?
analytical error
Transportation of a numeric critical value in transmitting a report is an what kind of error?
postanalytical error
blood from the wrong patient is an example of what?
preanalytical error
specimen collected in the wrong tube is an example of what?
preanalytical error
quality control outside of the acceptable limits in an example of what?
analytical error
proficiency testing is required by CLIA for what?
–nonwaived tests
–FDA cleared and approved moderate-complexity or high-complexity assays