Lab Operations & Math

Accuracy

Term for agreement of results with the true value:

Mean

Term for average:

Median

Term for the middle value:

Mode

Term for the most common value:

Precision

Term for reproducibility:

Standard Deviation

What is the statistical measure of precision?

s = √(∑(X- x̄)^2 /(n-1)

What is the formula for Standard Deviation?

20

What's the minimum number of analyses needed to calculate Standard Deviation?

68%

What % of values fall within 1 sd?

95%

What % of values fall within 2 sd?

99%

What % of values fall within 3 sd?

Coefficient of Variation

What expresses relative Standard Deviation as a percentage?

CV (%) = s(100)/x̄

What's the formula for Coefficient of Variation?

Analytical Sensitivty

Term for the ability to detect small concentrations of a substance:

Diagnostic Sensitivity

Term for the ability to produce a positive result of the patient has the disease:

Analytical Specificity

Term for the ability to measure only the substance of interest:

Diagnostic Specificity

Term for the ability to produce a negative result of the patient does not have the disease:

Random Error

What kind of error category do instrument errors, sample errors, and human errors fall under?

Instrument errors

What kind of errors are voltage fluctuations and incorrect sample volumes?

Sample errors

What kind of errors are anticoagulant interference, drug interference, lipemia, and hemolysis?

Human errors

What kind of errors are improper preparation and/or storage of control reagents?

System Error

What error category are instrument errors and standard/reagent decomposition?

Laboratory Information System

What does LIS stand for?

Levey-Jennings chart

What displays trends and shifts in quality control?

Pre-analytical variables

What kind of variables happen before testing?

Pre-analytical variables

What kind of variables are specimen collection issues, transport, and preservatives?

Analytical variables

What kind of variables happen during testing?

Analytical variables

What kind of variables are test processing and QC data?

Post-analytical variables

What kind of variables happen after testing?

Post-analytical variables

What kind of variables are result evaluation, reporting, documenting, corrective action, turn-around time, and complaint resolution?

Reference Range

Term for the range in which 95% of the population is expected to fall:

2 sd

Random samples fall within how many standard devations?

Standard

Term for a substance with a known concentration:

Primary standard

What kind of standard is chemically pure, weighed, and measured directly?

Secondary standard

What kind of standard's assayed value is established by the reference range/comparison?

Control

Term for a substance having a known of determined range of values

Assayed control

What kind of control has values stated by the manufacturer?

Unassayed control

What kind of control does not have given values and its range needs to be determined?

Confidence Interval

Term for a range of values in which the control result must fall:

20

How many times must a control be analyzed to establish a confidence interval?

1:2s

One observation exceeds the ±2s range:

1:2s

1:3s

One observation exceeds ±3s:

1:3s

2:2s

Two consecutive observations exceed the mean +2s or -2s:

2:2s

R:4s

One observation exceeds +2s and then -2s:

R:4s

4:1s

Four consecutive observations exceed +1s or -1s:

4:1s

10x

Ten consecutive observations fall on one side of the mean:

10x

1:2s

What is the only Westgard warning rule?

100

What's the minimum number of individuals needed to establish a reference range?

Number of moles of a substance/liter of solution

What is Molarity?

Gram Molecular Weight

What does GMW stand for?

M = grams per liter/GMW

What's the formula for Molarity given grams?

M = % x 10/GMW

What's the formula for Molarity given %?

mM = mg per liter/GMW

What's the formula for mM?

V1C1 = V2C2

What's the formula for changing concentration?

weight 1/volume 1 = weight 2/volume 2

What's the formula for changing volume without changing concentration?

part/whole x 100

What's the formula to convert to a percentage?

10^3 (1,000)

Conversion factor for kilo:

10^-3 (0.001)

Conversion factor for milli:

10^-6 (0.000001)

Conversion factor for micro:

10^-9 (0.000000001)

Conversion factor for nano:

10^-12 (0.000000000001)

Conversion factor for pico:

A = abc

What's the formula for Beer's law given absorptivity, light pattern, and concentration?

A = log(100/%T)

or

A = 2 - log(%T)

What's the formula for Beer's law given transmittance?

Absorbance

What is 'A' in Beer's law?

absorptivity

What is 'a' in Beer's law?

Light pattern (cm)

What is 'b' in Beer's law?

Concentration

What is 'c' in Beer's law?

Transmittance

What is '%T' in Beer's law?

Spectrophotometry

Measurement of light in a narrow wavelength range; wavelength selected by prisms, gratings, or filters:

Fluorometry

Energy emission that occurs when certain compounds absorb electromagnetic radiation, become excited and return to energy levels slightly lower than their original energy levels:

Turbidimetry

Measures the amount of light blocked by particulate mater as light passes through the cuvette by a colorimeter or spectrophotometer:

Nephelometry

Measures light that is scattered by small particles at right angles to the beam incident to the cuvette:

Osmometry

Measure of total number of dissolved particles in a solution:

Chromatography

Separates mixture into individual components on basis of specific differences in physical characteristics:

Electrophoresis

Method for the physical separation of proteins based on their ionic charge and molecular size:

Tungsten lamp

What's used as source of light in the visible range in a spectrophotometer?

Hydrogen discharge/Deuterium lamp

What's used as a source of UV light in a spectrophotometer?

Hydrogen lamps/Deuterium lamps

Solutions of stable chromogens

What checks wavelength accuracy when calibrating the wavelength in a spectrophotometer?

Holmium oxide/Didymium filters

What is used to check wavelength calibration for a spectrophotometer?

Light Amplification by Stimulated Emission of Radiation

What does LASER stand for?

Flow Cytometry

Measurement of cell properties using light in a fluid medium:

All blood/body fluids are potentially infectious

What is standard precautions?

Exposed to bloodborne pathogens on a daily basis

Category 1 OSHA exposure:

Regularly exposed to bloodborne pathogens

Category 2 OSHA exposure:

Never exposed to bloodborne pathogens

Category 3 OSHA exposure:

Category 1 and 2

Which OSHA exposure categories need Hep B vaccines?

1:10 bleach solution

What is used to clean biohazard spills?

HIV

HBV

HCV

What are the three major bloodborne pathogens?

Biological safety cabinet

What provides safe manipulation of infectious material by redirecting airflow through a filter?

Department of Transportation (DOT)

US Postal Service (USPS)

Who regulates packing and transporting of specimens?

Occupational Safety and Health Administration

What does OSHA stand for?

OSHA

What federal agency regulates employee safety and enacts "Right to Know"?

Chemical Hygiene Plan (CHP)

Term for a written plan that states what to do in case of a chemical spill, fire, or exposure:

Safety Data Sheet

What does SDS stand for?