Clinical Chemistry: Midterm

Bias:

Systematic error in collecting or interpreting data, such that there is overestimation or underestimation, or another form of deviation of results or inferences from the truth.

External Validity

The degree to which the results of a study companies, and society. can be generalized to the population as defined by the 13. Discuss the usefulness of clinical practice guidelines and clinical inclusion criteria of the study.

Internal Validity

The degree to which the results of a study can be trusted; for the sample of people being studied.

Reference Standard

The best available method for establishing the presence or absence of the target disease or condition; this could be a single test or a combination of methods and techniques.

Systematic Review

A methodical and comprehensive review of all published and unpublished information about a specific topic to answer a precisely defined clinical question.

Validity

the degree to which a test or study measures what it purports to measure.

laboratory medicine

It refers to the discipline involved in the selection, provision, and interpretation of diagnostic testing that uses primarily samples from patients.

Testing

It is also used to establish and monitor the severity of a physiological disturbance.

Core Laboratories

It provide all high-volume and emergency testing in many hospitals, depend on automa- tion, informatics, computers, quality control, and quality man- agement.

Evidence-based Laboratory Medicine

It is the conscientious, judicious, and explicit use of the best evidence in making decisions about the care of individual patients

silo budgeting

Addresses only laboratory costs without consideration of benefit outside the laboratory

Analvte

A substance or constituent for which the laboratory conducts testing.

Buffer

A solution or reagent that resists a change in pH upon addition of either an acid or a base.

Dilution

The process (diluting) of reducing the concentration of a solute by adding additional solvent.

Gravimetry

The process of measuring the mass (weight) of a substance.

Half-Life

The time period required for a radionuclide to decay to one-half the amount originally present.

Solution

Is a homogeneous mixture of one or more solutes dispersed molecularly in a sufficient quantity of a dissolving solvent

titer

It is thought of as the lowest dilution at which a particular reaction takes place.

Henry's law

It states that the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid at equilibrium

unit

It identifies the dimension-mass, volume, or concentration-of a measured property.

number

The __________indicates how many units are contained in the property

derived unit

It is derived mathematically from two or more base units

pure

The preparation of many reagents and solutions used in the clinical laboratory requires "______" water.

Distillation

It is the process of vaporizing and condensing a liquid to purify or concentrate a substance or to separate a volatile substance from less volatile substances.

Distillation

It is the oldest method of water purification.

Ion exchange

Is a process that removes ions to produce mineral- free deionized water.

Reverse osmosis

is a process by which water is forced through a semipermeable membrane that acts as a molecular filter.

Ultraviolet oxidation

Is another method that works well as part of a total system.

Type III

____ water may be used for glassware washing.

Type II

____________water is used for general laboratov testing not requiring type I water.

Type I

_______water should be used in test methods requiring minimal interference and maximal precision and accuracy.

1 week

the maximum interval in the testing cycle for purity of reagent water should be _______

reagent or analytical reagent grade

Chemicals that meet specifications of the American Chemical Society (ACS) are described as _________

Lot-analyzed reagents

Each individual lot is analyzed and the actual amount of impurity reported

Maximum-impurities reagent

Reagents which maximum impurities are listed.

USP and NF Grade

chemicals produced to meet specifications set down in the United States Pharmacopeia

T

T or F: Chemicals labeled purified, practical, technical, or commercial grade should not be used in clinical chemical analysis without prior purification.

Primary reference materials

Are highly purified chemicals that are directly weighed or measured to produce a solution whose concentration is exactly known.

Secondary reference materials

Are solutions whose concentrations cannot be prepared by weighing the solute and dissolving a known amount into a volume of solution.

Class A

________glassware is certified to conform to the specifications outlined in NIST circular (2-602

Pipettes

Are used for the transfer of a volume of liquid from one container to another.

transfer pipette

It is designed to transfer a known volume of liquid.

Transfer pipettes

They consist of a cylindrical bulb joined at both ends to narrower glass tubing.
A calibration mark is etched around the upper suction tube, and the lower delivery tube is drawn out to a gradual taper.

Volumetric transfer pipette

Is calibrated to deliver accurately a fixed volume of a dilute aqueous solution.

Ostwald-Folin pipettes

Are similar to volumetric pipettes but have their bulb closer to the delivery tip and are used for the accurate measurement of viscous fluids, such as blood or serum

top

When filled with opaque fluids, such as blood, the ____ of the meniscus must be read.

Measuring pipettes

T his is a piece of glass tubing that is drawn out to a tip and graduated uniformly along its length

Mohr pipette

Pipette that is calibrated between two marks on the stem.

Serological pipette

Has graduated marks down to the tip.

Serological

___________pipettes have a larger orifice than do the Mohr pipettes and thus drain faster

Micropipettes

Are pipettes used for the measurement of micro- liter volumes

Micropipettes

Are generally available in small sizes, ranging from 1 to 500pL

Volumetric flasks

Are used to measure exact volumes; they are commonly found in sizes varying from 1 to 4000 mL.

clinical chemistry

is involved in the analysis of biochemical byproducts found in biological fluids, such as serum, plasma, or urine, making purification and a known exact composition of the material almost impossible.

secondary standard

is a substance of lower purity with concentration determined by comparison with a primary standard.

Water

is the most frequently used reagent in the laboratory.

Type III

is acceptable for glassware washing but not for analysis or reagent preparation.

Type I

water was used for test methods requiring minimum interference, such as trace metal, iron, and enzyme analyse

Type II

water was acceptable for most analytic requirements, including reagent, quality control, and standard preparation

resistance

As purity increases, ____________also increases.

Percent solutions

is expressed as equal parts per hundred or the amount of solute per 100 total units of solution.

Molarity

is expressed as the number of moles per 1 L of solution

Molality

represents the amount of solute per 1 kg of solvent.

Normality

It is defined as the number of gram equivalent weights per 1 L of solution.

valence

is the number of units that can combine with or replace 1 mole of hydrogen ions for acids, hydroxyl ions for bases, and the number of electrons exchanged in oxidation reduction reactions.

Dilute solution

is one in which there is relatively little solute.

concentrated solution

has a large quantity of solute in solution

saturated solution

A solution in which there is an excess of undissolved solute particle

supersaturated solution

has an even greater concentration of undissolved solute particles than a saturated solution of the same substance.

Vapor pressure

is the pressure at which the liquid solvent is in equilibrium with the water vapor

Freezing point

is the temperature at which the vapor pressures of the solid and liquid phases are the same.

Boiling point

is the temperature at which the vapor pressure of the solvent reaches one at- mosphere.

Osmotic pressure

is the pressure that opposes osmosis when a solvent flows through a semipermeable mem- brane to establish equilibrium between compartments of differing concentration.

Redox potential

Is a measure of the ability of a solution to accept or donate electrons.

Reducing agents

Substances that donate electrons

Oxidizing agents

Substances that accept electrons

Conductivity

is a measure of how well electricity passes through a solution

Resistivity

The reciprocal of conductivity, is a measure of a substance’s resistance to the passage of electrical current.

ohms

Resistivity or resistance is expressed as ______

buffer

Are weak acids or bases and their related salts that, as a result of their dissociation characteristics, minimize changes in the hydrogen ion concentration.

pH

Hydrogen ion concentration is often expressed as ___

Henderson-Hasselbalch

equation, which mathematically
describes the dissociation characteristics of weak acids and bases and the effect on pH:

Ionic strength

is the concentration or activity of ions in a solution or buffer

Liquid-in-glass

___________ thermometers use a colored liquid (red or other colored material) or mercury encased in plastic or glass material with a bulb at one end and a graduated stem. They usually measure temperatures between 20°C and 400°C.

Partial immersion thermometers

are used for measuring temperatures in units such as heating blocks and water baths and should be immersed to the proper height as indicated by the continuous line etched on the thermometer stem.

Total immersion thermometers

These thermometers are used for refrigeration applications,

Surface thermometers

These thermometers may be needed to check temperatures on flat surfaces, such as in an incubator or heating oven.

Kimax/Pyrex

Borosilicate

Corex

Akuminosilicate

Vycor

Acid and alkali resistant glassware

volumetric flask

A Class A___________ is calibrated to hold one exact volume of liquid (TC). The flask has a round, lower portion with a flat bottom and a long, thin neck with an etched calibration line.

Volumetric flasks

re used to bring a given reagent to its final volume with the prescribed diluent

Volumetric flasks

Are used to bring a given reagent to its final volume with the prescribed diluent

Griffin beaker

has a flat bottom, straight sides, and an opening as wide as the flat base, with a small spout in the lip.

Erlenmeyer flask

has a wide bottom that gradually evolves into a smaller, short neck.

Graduated cylinders

are long, cylindrical tubes usually held upright by an octagonal or circular base.

Pipets

are glass or plastic utensils used to transfer liquids; they may be reusable or disposable.

blowout pipet

as a continuous etched ring or two small, close, continuous rings located near the top of the pipet

Self-draining pipet

allows the contents of the pipet to drain by gravity.

Mohr

The tip of the pipet should not be in contact with the ac- cumulating fluid in the receiving vessel during drainage. With the exception of the _____pipet, the tip should remain in contact with the side of the vessel for several seconds after the liquid has drained.