1010 unit 3 Flashcards
1
Q
what is a control?
A
represents a specimen with a known value that is similar in compositions to the patients sample
2
Q
describe random errors
A
errors that affect the reproductivity of a test system. associated with 1-32, R-4s, and outliers
3
Q
what is sensitivity?
A
defined as the proportion of cases with a specific disease that gives a positive test result. those results are truly positive
4
Q
what is an analyte
A
substance or constituent being measured
5
Q
how do you develop a reference range?
A
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
6
Q
what is osmolarity formula?
A
osmoles of solute per liter of solution
7
Q
what is quality assurance/assessment
A
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
8
Q
what is specificity?
A
defined as the proportion of cases with the absence of the specific disease that gives a negative test result. Those tests are truly negative
9
Q
what is the warning rule where 1 control value outside +/- 2SD?
A
1-2s
10
Q
what is proficiency testing?
A
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
11
Q
what are reference values?
A
“normal values”, the laboratory must provide reference values for the physician so that they know what is considered normal for that assay
12
Q
what is standard deviation?
A
statistical term for the mathematical expression of a guassian curve. Measures the scatter of dat around the mean of a guassian distribution
13
Q
what is mean?
A
average of set of numbers
14
Q
what are standards?
A
highly purified substances of a known composition. used to calibrate and measure accuracy
15
Q
what is median?
A
middle value of body of data
16
Q
10x
A
rejection rule, 10 consecutive points are all above or below the mean
17
Q
what is the rejection rule for 2 consecutive control values outside of -/+ 2SD
A
2-2s
18
Q
what is the rejection rule for 1 control value outside of -/+ 1 SD?
A
1-3s
19
Q
what is mode?
A
value that occurs most commonly in the mass of data
20
Q
what are systemic errors?
A
–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
21
Q
what is CV%?
A
(SD/mean) x 100 = CV%
–helpful is comparing precision differences among assays and methods
22
Q
what is calibration?
A
comparison of the measurements of an instrument or glassware to a known physical constant
23
Q
what is a trend?
A
four consecutive control values moving in one direction
24
Q
what is a shift?
A
four consecutive control values all above or below the mean
25
what are some sources of systemic errors
--worn pump tubing
--decreased bulb output
--improperly calibrated pipettor
26
how often is a control value expected to fall outside of 2SD?
1 in 20 runs
27
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
28
what is "out of control"
a problem observed determining that patients results cannot be reported
29
what are some sources of random errors?
--worn pump tubing
--varying bulb output
--technique
-unstable reagent,
--unstable environment
30
68% of all values in a measured group fall within this area
1SD
31
what is the rejection rule that is 1 control value exceeds the mean +2SD and 1 control value exceeds -2SD?
R-4s
32
99.7% of all the values in a measure group fall within this area
3SD
33
95% of all values in a measured group fall within this area
2SD
34
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
35
quality management consist of what?
--quality assurance
--quality control
36
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
37
The CLIA '88 amendment regulations established minimum requirements with general QC systems for what?
all nonwaived testing
38
the abbreviation TJC stands for an organization that does what ?
accredits hospitals and inspects clinical laboratories
39
the abbreviation CAP stands for an organization that does what?
accredits only hospital laboratories only
40
the abbreviation for COLA stands for an organization that does what?
accredits physicians offices
41
the abbreviation for CLIA stands for an organization that does what?
determines minimum QC requirements for nonwaived assays
42
ISO 15189 is intended for what use?
medical laboratories
43
six sigma management focuses on what?
reduction of variability in laboratory results
44
what does CLIA '88 require?
participation in proficiency testing
45
if the incorrect anticoagulant is in a blood collection tube, it is a what?
an active error
46
incorrect identification of a patient is what kind of error?
preanalytical error
47
malfunction of a microprocessor that affects accuracy in testing is what kind of error?
analytical error
48
Transportation of a numeric critical value in transmitting a report is an what kind of error?
postanalytical error
49
blood from the wrong patient is an example of what?
preanalytical error
50
specimen collected in the wrong tube is an example of what?
preanalytical error
51
quality control outside of the acceptable limits in an example of what?
analytical error
52
proficiency testing is required by CLIA for what?
--nonwaived tests
--FDA cleared and approved moderate-complexity or high-complexity assays
53
if proficiency testing is not available for a specific analyte, what one alternate assessment needs to be conducted?
internal split-sample analysis
54
the delta check cutoff value may be presented as what?
--absolute change
--percent change
--rate of change
55
quality control evaluates the _________ phase of testing
analytical
56
what is the most encountered laboratory testing error?
systemic error
57
what is the "matrix" of a specimen?
--has components of a specimen other than the analyte of interest
--more closely resembles the patient specimen
58
precision is defined as what?
how close results are to one another
59
what is the coefficient of variation?
equal to SD divided by mean
60
what does total analytical error depend on?
-methods precision
-method accuracy
61
what does Levy- Jennings plots show?
values on a chart
62
when a specimen is transported to the laboratory, what is the optimum time for collection?
within 2 hours of collection
63
what is biometrics?
the science of statistics applied to biological observations
64
what is a major advantage of POCT?
--faster turnaround time
--lower cost
65
POCTs assays are usually in which CLIA category?
waived
66
over the counter kits are usually in which CLIA catergory?
waived
67
hemoglobin determination is an early example of what?
decentralized health care
68
an early commercial example of direct consumer genetic testing is:
cholesterol assay
69
what is the concentration at which most sensitive current laboratory assays can give a positive serum hCG result?
100 mIU/mL
70
the most specific assays for human chorionic gonadotropin (hCG) use antibody reagents against which subunit of hCG?
Beta
71
what is an important characteristic to be considered when selecting?
rapid turnaround time
72
what is the tricorder is modeled after?
original cell counters
73
what is the ultimate goal of the laboratory?
quickly produced results
74
what can computer technology be used for?
inventory control
75
what is the function of CPU?
exchange of information
76
what is the function of an interface?
short term memory
77
the laboratory can have directly connected computers that can access the hospital record system by what?
forming an LAN
78
what is an example of laboratory information system functionality?
quality control
79
what are some future challenges for laboratory automation standards?
developing uniform collection devices
80
what is the major benefit of laboratory automation?
faster turnaround time
81
what are steps in automation designed to mimic manual techniques?
pipetting of reagents
82
Define quality
Worth if services
83
What are 5 non analytical factors if quality assessment?
1) established laboratory policies
2) qualified personnel
3) appropriate methodology
4) laboratory procedure manual
5) proper procedure for specimen collection and storage
84
What are 2 analytical factors in quality assessment?
1) application of statistical analysis of results in quality assessment protocols
2) instrumental applications of statistics to measurements
85
What does Quality Assurance ensure?
Reliability of results
86
Functions of quantitative quality control program
1) provides guide to function equipment, reagents, and individual technique
2) confirms accuracy of testing when compared with reference values
3) detects increase in frequency (dispersion)
4) detects progressive drift values to one side of mean for Atleast 4 days (trend)
5) demonstrates abrupt shift/change from mean for 4 dAys in a row (shift)
87
What is process improvement?
QA and TQI are driven by pressure to contain the cost of good service
88
10 step monitoring process
1) assign responsibility for QA
2)define the scope of patient care
3) identify important aspects of care
4) construct indicators
5) define threshold for evaluation
6) collect and organize data
7) evaluate data
8) develop corrective action plan
9) assess actions; document improvement
10) communicate relevant information
89
What are the assessment requirement s?
1) request form must be completed by the physician directing patient care
2) time of receipt of specimen
3) request form must be clean and legible
4) information on accompanying specimen container must match request form
5) lab can accept only properly labeled specimens, if not the specimen is rejected
6) all containers must be labeled by the person doing the collection
7)specimens must be transported to lab in safe, timely, efficient manner.
8) specimens must be checked for acceptability
90
What are some components of a CAP QA program
1) procedure manuals
2) comparison on test results
3) proficiency testing
4) communications
91
What are major difficulties in guaranteeing reliable results invoiced in sampling procedure?
—Time of day —> circadian rhythms
— patients position —> lying or standing
— patients physical ability —> bed, ambulatory, or physically active
— interval of eating —> fasting
—time interval from blood collection to processing in lab
—storage containers
92
What are some procedural factors that can cause variance?
—aging of Chemicals/reagents
— personal bias of techs
__ laboratory bias due to —> environment, methods, apparatus
—changes in instruments
— changes in personnel
93
What is needed to determine sensitivity and specificity?
1) tests positive
2) tests negative
3) disease present (positive)
4) disease absent (negative)
94
What is true positive and true negative?
True positive —> subjects who have a positive result and also have the disease in question
True negative —> subjects who have a negative result and do not have disease in question.
95
What is false positive and false negative?
False positive —> subject who test positive but does not have disease in question.
False negative —> subject who test negative but do have disease in question
96
Those tests that are negative are try negative describes what?
Specificity
97
Results that are positive are truly positive describe?
Sensitivity
98
Normals are based on what?
Patient population
99
How to ensure clinically correct results ?
1) standards
2) control samples
3) proficiency testing programs
100
What are some characteristics of control specimen?
1) similar in composition to unknown specimen
2) has known concentration
3) is included in every batch or run
4) treated same way as patient specimen
5) results must fall within the set QC rules to report patient results
101
What is objective of controlling reliability of the laboratory results?
Reject results when there is evidence that more than the permitted amount of error has occurred
102
What should be on a control bottle?
— date of reconstitution
—date of expiration
— tech initials
103
What are characteristics of a control
— must be run at room temperature
— must be kept closed and refrigerated between runs
— data collection—> must mimic all conditions found when actually running controls during year
—must be run over a period of time
— must be Atleast 30 but the larger the better
104
What are the 3 control values?
—abnormal high
—normal
—abnormal low
105
A value may fall above the mean how often?
2.5% —> 1 out of 40
106
A value may fall below mean how often?
2.5% —> 1 out of 40 runs
107
What determines precision of CV?
The closer CV is to 1, the better the precision
108
What are CVS used for?
—comparison of methods
— comparison of labs
109
Define aliquot
A portion of a total amount of a solution or suspension
110
Define percent
—One part in every hundred
OR
—g or mL of solute per 100 mL of solution
111
What is PV
Photovoltaic cell—> an energy harvesting technology that converts solar energy into useful electricity
112
What is PPV?
Positive predictive value —> likelihood that an individual with a positive test result truly has the particular gene and/or disease in question
113
What is POCT?
Point of care testing—> testing that is performed near it at the site of a patient with the result leading to possible change in the care of the patient
114
What is waived testing?
Those tests that are determined by CDC or FDA to be so Simple that there is little risk of error
115
Define moderately complex tests
One requiring basic lab knowledgeable and training for personnel performing the test
116
What are high complexity tests?
Those that require clinical laboratory expertise beyond normal automation to perform
117
What are exponents used for?
To indicate that a number must be multiplied by itself
118
What are positive exponents
Indicates the number of times the base is to be multiplied by itself
119
What are negative exponents?
—Indicates the number of times the reciprocal of the base is to be multiplied by itself
—negative exponents represent a fraction
120
Define density
The amount of matter per unit volume of substance
121
Define specific gravity?
The weight of 1 mL of a solution compared to weight of 1 mL if pure water at 4 C
122
Define proportions
Are a way of saying that two ratios are equal
123
Define concentration of the solution
Amount of one substance relative to the amount of the other substances in the solution and is expressed in several ways (weight, volume per unit volume, or percent)
124
What can never happen to dilution?
Increase it
125
What is a mole?
The molecular weight of a compound in grams
126
How to perform a single dilution?
1 unit of the original specimen diluted to a final volume of 2, 5, or 10 units
127
Serial dilution procedure
1) tube 1 contains 1 mL of undiluted serum —> 1:1 dilution
2) tube 2 contains 1 ml of undiluted serum + 1 mL diluent —> 1:2dilution ( 1/2 x 1 = 0.5 ml of serum)
3) tube 3 contains 1 ml of 1:2 diluted serum + 1 ml of diluent —> 1:4 dilution ( 1/4 x 1 = 0.25 ml of serum)
4) tube 4 contains 1 ml of 1:4 diluted serum + 1 ml of diluent —> 1:8 dilution (1/8 x 1 = 0.125 ml of serum)
5) tube 5 contains 1 ml of 1:8 serum + 1 ml of diluent —> 1:16 (1/16 x 1 = 0.06 ml of serum)
128
what are two types of error analysis? what are they?
1) active error --> obvious. occurs at interference of healthcare worker and the patient
2) latent errors --> relative to the organization or design of a laboratory
129
what do standards test best?
accuracy and used to establish reference points to construct graphs
130
describe how accuracy and precision relate
accuracy IS precision with calibration
