Lab Math defenitions
Solute:
Is a substance dissolved in a mixture
Density:
Amount of matter per unit volume
Calibration:
The process of checking, using standard
solutions, adjusting a method or instrument so it yields accurate results
Reportable Range:
Span of test values which lab establishes the accuracy of an instrument
Accuracy:
Closeness of a result to the true value
Predictive Values:
Means or ability to predict the results of an analysis of the same data by using another test instrument. It contributes to the validity of the test
Sensitivity:
Is a measure of the number of patients with a disease who test positive relative to the total number of patients who test positive. Sensitivity provides us with the percentage of true positives
Scientific International Unit:
Modified metric system to ensure results are consistent in any part of the world
Blind patient control:
Used in place or addition to a commercial control
Confidence Intervals:
The reference range is expressed using 2SD on either side of the mean, with 95% of the values falling above and below the mean.
Also referred to as confidence limits
Proportion:
2 or more ratios having the same relative meaning but with different numbers
Panic Value:
Is a patient’s lab result that is life-threatening if action is not taken quickly
Reagent:
Any substance used to produce a chemical reaction
Meter:
The base unit of measurement of distance
Levy-Jennings Chart:
Daily quality control record
Celcius:
measurement of temperature
Reference Range:
same as normal range
Gram % Solution:
Percentage of gram weight in a solution
Blank Solutions:
Are used to ensure that the results obtained in the lab reflect only the presence of the analyte and not some other factor
Gram:
unit of weight
Normal Range:
Is the range of results that are expected to be found when a healthy individual is tested
Technical Grade:
Chemicals used for industrial purposes
Percent:
A value expressed as part of 100
Specificity:
Is a measure of the number of patients with no disease who test negative relative to the total number of patients who test negative. Specificity provides us with the percentage of true negatives
Controls:
Material or solution with a known concentration of the analytes being measured
Standard:
Chemical solution of a known concentration that can be used as a reference or calibration substance
Quality Assurance:
Encompasses every aspect of laboratory testing beginning with the physician ordering a test and ending when they receive the laboratory report with the test results
Exponent:
Is used to indicate that a number must be multiplied by itself as many times as indicated by the exponent. Example 10^10, 10 is multiplied by itself 10 times
Molality:
Refers to the number of moles per kilogram of solvent. It is expressed as a concentration of weight per unit
Stock Solution:
Concentrated solution used to make up working solutions
V/V Solution:
Volume to volume solution; 2 liquids
Molarity:
Refers to the number of moles of solute per litre of solution. A mole is the number of grams of a substance that is equal to its atomic or molecular weight. Its importance is useful to know how many molecules are present for a reaction to take place.
Ratio:
Example 1:4 where the first number represents the parts of the substance used and the second number the parts of the solvent used
W/V Solution:
Weight to volume solution; the amount of solute in a solvent
Solution:
Is a mixture of 2 or more pure substances. In a solution, 1 pure substance is dissolved in another pure substance homogenously
Median:
The middle value of an entire data set
pH:
Hydrogen ion concentration
Quality Control:
Is part of QA which involves the processes undertaken during the actual testing of the patient samples to ensure that the test results are reliable
Osmolality:
Is the number of osmoles of solute per kilogram of solvent
Dilution:
A weaker solution made from a stronger solution
Litre:
Base unit to measure volume
Proficiency Testing:
Program under which samples are sent to a group of laboratories for analysis. Results are compared with the laboratories participating in the program
Mean:
Average calculated from a series of numbers
Mode:
The number that comes up the most (the value that appears most frequently in a set of data)
Reliability:
Depending on test results to be accurate
Standard Deviation:
Is a measure of the spread or dispersion of a set of data
Coefficient of Variation:
Shows variability between 2 different sets of values
Analytical grade:
The most pure grade of chemical
Fahrenheit:
measurement of temperature
Precision:
Repeated results give the same value
Working Solution:
Is the solution for use; made from a stock solution
Westgard’s Rules:
Is a set of rules to determine if a method is in or out of control
Significant Figure or Digit:
a number whose accuracy is reliable
Specific Gravity:
Is a measurement of density, a ratio of the mass of a substance relative to water
Concentration:
Amount of 1 substance relative to the amount of another substance in a solution
Scientific Notation:
Is reducing large numbers by using exponents
Solvent:
A substance in which something is dissolved; for example water
Gaussian Curve:
Distribution of values around the mean
Therapeutic Range:
Range of results that refers to either the dosage range or blood concentration usually expected to achieve desired therapeutic effects
Mole:
A fundamental unit of mass used by chemists. This term refers to a large number of elementary particles; atoms, molecules, ions, electrons
Osmolarity:
Number of osmoles of solute per litre of solution
Osmole:
a unit of osmotic pressure equivalent to the amount of solute that dissociates in solution to form one mole (6.02 x10^23) of particles