315 Chapter 1: Basic Principles and Practices of Clinical Chemistry — Vocabulary Flashcards

A vocabulary-style set of flashcards covering key concepts, terms, and definitions from Chapter 1: Basic Principles and Practices of Clinical Chemistry.

SI units (Système International d'Unités)

International metric-based units adopted in 1960; lab results are expressed as a numeric value with a unit, reflecting the physical quantity.

Traditional lab units

Common non-SI units (e.g., mg/dL) still used in some reports; SI units are globally recommended by bodies like IFCC and WHO.

atto (a)

SI prefix meaning 10^-18.

femto (f)

SI prefix meaning 10^-15.

pico (p)

SI prefix meaning 10^-12.

nano (n)

SI prefix meaning 10^-9.

micro (μ)

SI prefix meaning 10^-6.

milli (m)

SI prefix meaning 10^-3.

centi (c)

SI prefix meaning 10^-2.

deci (d)

SI prefix meaning 10^-1.

kilo (k)

SI prefix meaning 10^3.

mega (M)

SI prefix meaning 10^6.

giga (G)

SI prefix meaning 10^9.

tera (T)

SI prefix meaning 10^12.

peta (P)

SI prefix meaning 10^15.

AR (Analytical Reagent)

Reagent grade meeting ACS purity standards, suitable for most clinical tests.

Ultrapure/Chemically Pure (CP)

Very high chemical purity; often used in specialized applications to avoid contamination.

USP/NF grade

Chemicals meeting purity requirements for drug manufacturing; suitable for certain buffers or standards but may not meet diagnostic testing precision.

Technical/Commercial Grade

Lowest purity; contains significant impurities; not suitable for clinical chemistry or patient testing.

Primary Standard

Highly pure, stable compound used to prepare solutions of known concentration; non-hygroscopic and easily weighed.

Certified Standard Reference Materials (SRMs, NIST)

Standards prepared and certified by NIST; provide traceability for instrument calibration and method validation.

Calibration

Process of adjusting an instrument’s response to match a reference material or standard to ensure accuracy.

Linearity studies

Assess whether a method’s output is proportional to analyte concentration across a range; required for method validation.

Type I water

Highest purity water used for critical assays (enzymes, trace metals, HPLC).

Type II water

General-purpose water for routine chemistry applications.

Type III water

Water used for washing glassware and initial preparations.

Distilled water

Water produced by boiling and condensation; removes many impurities; may need further purification for sensitive tests.

Deionized water

Water purified by ion-exchange resins to remove cations and anions; lowers conductivity.

Reverse osmosis

Water purification using a semi-permeable membrane under pressure to remove dissolved contaminants.

Filtration

Removal of particulates and microorganisms; often part of final polishing of water.

Solute

Substance dissolved in a solvent.

Analyte

Substance of interest being measured in a lab test.

Solvent

Medium in which solutes are dissolved; typically water in clinical chemistry.

Solution

Homogeneous mixture of solute(s) and solvent; described by concentration units.

Percent solution (w/v, v/v, w/w)

Solute per 100 total units of solution; examples include weight/volume, volume/volume, and weight/weight percent.

Molarity (M)

Moles of solute per liter of solution (mol/L); temperature can affect volume.

Molality (m)

Moles of solute per kilogram of solvent (mol/kg); independent of temperature.

Normality (N)

Gram equivalents of solute per liter of solution; depends on the reaction type (acid-base, redox, etc.).

Osmolarity

Osmoles of solute per liter of solution (Osm/L).

Osmolality

Osmoles of solute per kilogram of solvent (Osm/kg).

pH

Negative logarithm of hydrogen ion concentration; measure of how acidic/basic a solution is.

Buffers

Weak acid and conjugate base system that resists pH changes; bicarbonate is a common physiological buffer.

Henderson–Hasselbalch equation

pH = pKa + log([A-]/[HA]); relates pH to buffer components and their concentrations.

pKa

Negative logarithm of the acid dissociation constant; pH at which a weak acid is 50% dissociated.

Beer's Law (Beer–Lambert Law)

A = ε × l × c; absorbance is proportional to concentration for a given path length and molar absorptivity.

Standard curve

Plot of absorbance versus known concentrations used to determine the concentration of an unknown sample.

Whole blood

Blood containing plasma and cells; usually collected with an anticoagulant.

Serum

Liquid portion after blood clots; lacks fibrinogen; used for many chemistry analyses.

Arterial blood

Blood drawn from arteries, used in blood gas analyses for O2, CO2, and pH.

Hemolysis

Rupture of red blood cells; releases intracellular components (e.g., K+, LDH) that can affect results.

Lipemia

Excess lipids in sample causing turbidity; interferes with spectrophotometric measurements.

Icterus

Elevated bilirubin causing yellowing; can interfere with many assays.

Pre-analytical factors

Variables before analysis (collection, handling, timing) that affect test results.

Chain of Custody

Documentation trail from collection to testing to reporting to ensure sample integrity.

LIS (Laboratory Information System)

Electronic system used for reporting, tracking, and managing lab results.

CAP/CLIA/HIPAA

Regulatory frameworks for quality standards, laboratory testing, and patient privacy.

RCF (relative centrifugal force)

RCF = 1.118 × 10^-5 × r × (rpm)^2; depends on rotor radius and speed.

Counterbalancing

Balancing tubes by placing equal volumes opposite each other to prevent rotor vibration.

Centrifuge types

Clinical centrifuges separate components; refrigerated units prevent heat; microcentrifuges and ultracentrifuges have specialized uses.

Safety in centrifugation

Keep lids locked during operation; perform maintenance; document calibration.

Desiccants

Drying agents used to maintain dryness inside desiccators (e.g., silica gel, Drierite).

Hydrates

Compounds that include water molecules in their crystal formula (e.g., CuSO4·5H2O).

Anhydrous

Compound with no water of crystallization.

Hygroscopic

Substances that readily absorb moisture from the air.

Desiccator

A sealed vessel used to store moisture-sensitive reagents; often contains a desiccant.

Balances (analytical vs electronic)

Analytical balances provide high precision (±0.0001 g); electronic balances are fast and user-friendly but require calibration.

Class A vs Class B glassware

Class A: highest accuracy for analytical use; Class B: lower tolerance for routine measurements.

To Contain (TC) vs To Deliver (TD)

TC: delivers nominal volume but residual liquid remains; TD: delivers exact volume when emptied.

Volumetric flasks

Glassware designed to prepare accurate, single-volume solutions; highly precise.

Erlenmeyer (flask)

Used for mixing, titration; not as precise as volumetric glassware.

Graduated cylinders

For approximate volumes; less precise than flasks designed for accuracy.

Measuring/Graduated pipettes

Pipettes used for delivering varying volumes; not exact like volumetric types.

Volumetric pipettes

Deliver a precise volume; calibrated to deliver a single fixed volume.

Ostwald-Folin and Pasteur pipettes

Transfer-type pipettes for moving liquids; not always highly precise.

Blowout vs Self-draining pipettes

Blowout routes require expelling the last drop; self-draining volumes include it in delivery.

Pipette calibration methods

Gravimetric (weighing) method and air-displacement method used to verify accuracy.