CLINICAL CHEMISTRY 1 - Laboratory Basics and Quality Control

A comprehensive set of vocabulary flashcards covering Clinical Chemistry laboratory fundamentals, including measurement systems, equipment, statistics, and analytical methodologies.

Clinical Chemistry

The area in the laboratory concerned with the analysis of body fluids for diagnostic purposes, derived from the Greek word "Kline" meaning "Bed".

Systeme international d'unites (S.I)

The international system of measurement units consisting of seven basic units: meter ($m$), kilogram ($kg$), second ($s$), mole ($mol$), Ampere ($A$), Kelvin ($K$), and Candela ($cd$).

Borosilicate glass

The most common type of laboratory glassware, such as Pyrex and Kimax, used for heating and sterilization.

Corex

A special alumina silicate glass that is chemically strengthened and is six times stronger than borosilicate glass.

Vycor

Glassware designed for high thermal shock and extreme chemical treatment with acids; it can be heated to $900^\circ\text{C}$.

Flint glass

A soda-lime glass composed of Calcium, Silicon, and Sodium oxides; it is easy to melt and used for disposable glassware.

Low actinic glass

Amber-colored glassware used to protect light-sensitive contents.

Volumetric pipet

A self-draining pipet designed for the delivery of non-viscous fluids; it should not be blown out.

Ostwald Folin pipet

A blow-out pipet, identified by etched rings, specifically used for measuring viscous fluids.

To Deliver (TD)

A classification of pipets that dispense the exact volume indicated on the glass.

To Contain (TC)

A classification of pipets that hold a specific volume but do not dispense that exact amount; mercury is used as the calibrating medium.

Centrifugation

The process of separating solid matter from a liquid suspension using centrifugal force, which depends on mass, speed ($rpm$), and radius ($r$).

Type 1 Water

The most pure grade of water used for special tests such as Immunoassays and DNA analysis; it must be used immediately and cannot be stored.

Analytic reagent

A grade of chemical suitable for most analytical laboratory procedures.

Serum

The fluid portion of clotted blood obtained after centrifugation.

Plasma

The fluid portion of anticoagulated blood obtained after centrifugation.

Batch testing

A laboratory processing mode where all samples are loaded at the same time and a single test is performed per sample.

Random access testing

A processing mode where any test can be performed on any sample in any sequence.

Primary standard

A highly purified chemical that can be measured directly to produce a substance of exact concentration and purity.

Accuracy

The nearness or closeness of an assayed value to the true or target value.

Precision

The ability of an analytical test to give repeated results on the same sample that agree with one another.

Mean

The mathematical average calculated as the sum of all data divided by the number of data points ($n$).

Standard Deviation (SD)

A descriptive statistic representing the average distance of all data points from the center (mean).

Coefficient of Variation (CV)

A value expressed as a percentage used to compare standard deviations ($SD$) with different units, calculated as $\text{CV (\%)} = \text{SD}/\text{mean} \times 100$.

Gaussian Curve

A bell-shaped population probability distribution symmetric about the mean where $68.3\%$ of values fall within $\pm 1 \text{ SD}$.

Intralab Quality Control

Internal QC used for daily monitoring of accuracy and precision to detect random and systematic errors.

Random Error

Unpredictable errors occurring by chance that vary from sample to sample, such as mislabeling, improper mixing, or voltage fluctuations.

Systematic Error

Errors that influence observations consistently in one direction, often caused by calibration problems or reagent deterioration.

Levey-Jennings Chart

Also known as a Shewhart or Dot chart, it is the most common graphic representation of acceptable limits of variation used to identify laboratory errors.

Trend

A pattern on a QC chart where control values either increase or decrease for six consecutive days, typically due to reagent deterioration.

Shift

A pattern where control values distribute themselves on one side of the mean for six consecutive days, often due to improper instrument calibration.

Delta check

A quality control technique that compares the difference between two consecutive measurements of the same analyte on the same individual.

Molarity (M)

The concentration of a solution expressed as the number of moles of solute per liter of solution.

Spectrophotometry

The measurement of light transmitted by a solution to determine the concentration of light-absorbing substances.

Beer's Law

The principle stating that an unknown concentration is directly proportional to absorbed light ($A$) and indirectly proportional to transmitted light ($\%T$).

Flame Emission Photometry

An analytical method that measures the light emitted by atoms that have been excited by a flame.

Atomic Absorption Spectrophotometry

A highly sensitive method that measures light absorbed by ground-state atoms using a hollow cathode lamp as a light source.