Laboratory Liquids and Water Purification Methods

Reagent Grade Water

Different types of water according to the Clinical and Laboratory Standards Institute (CLSI) and their uses.

Water Purification Methods

Different methods classified by their means of purification and end resulting water type.

Grades of Chemicals

Differing grades of chemicals and how they're used within the clinical laboratory.

Reagent

A substance used in a chemical reaction to detect, measure, or produce other substances.

Patient Sample

A specimen taken from a patient for analysis.

Calibrator

A substance with a known concentration used to set the scale of a measurement instrument.

Control

A standard used to ensure that a test is working correctly.

Proficiency Testing Material

Samples used to assess the performance of a laboratory in testing.

Reference Range

The range of values that is considered normal for a healthy population.

Acceptable Range

The range of values within which a test result is considered acceptable.

Reagent Water

Water that is suitable for use in a specified procedure and does not interfere with the specificity, accuracy, and precision of an assay procedure.

Resistivity

Tendency of water without ions to resist conducting electricity; measured in Ohms (Ω) or Mega Ohms (MΩ).

Conductivity

Tendency of water that contains ions to conduct electricity; measured in Siemen (S) or micromho/cm.

Total Organic Carbon (TOC)

Measurement of organic contaminants found in water; unit of measure is parts per million (ppm) or parts per billion (ppb).

Viable Plate Count

Indicator of microbial contamination.

Clinical Laboratory Reagent Water (CLRW)

Purity satisfies most routine clinical laboratory testing.

Special Reagent Water (SRW)

Defined by the lab for procedures that need different specifications than CLRW.

Instrument Feed Water

Water specifications provided by manufacturer for internal rinsing, dilutions, and water bath function.

Commercially Bottled, Purified Water

Packaged to protect it from environmental contamination or degradation during transport and storage.

Autoclave and Wash Water

Water for autoclaves and automatic laboratory dishwashers, purified to low levels of impurities.

Distillation

Process of boiling water and cooling the resulting steam to produce distilled water.

Deionized Water

Water passed through a resin column to remove ionizable substances.

Reverse Osmosis

Process where water under pressure moves through a semipermeable membrane to remove dissolved solids and impurities.

Analytical Reagent (AR) Grade

High degree of purity used for preparing reagents in clinical laboratory.

Chemically Pure (CP) Grade

May not be sufficient for all laboratory procedures; limits of tolerated impurities are not indicated.

USP and NF Grade

Less pure than CP-grade chemicals; tolerances are related to health rather than chemical purity.

Technical or Commercial Grade

Least pure grade, used for industrial purposes and not in clinical laboratory testing.

Reagents

Any substance used to produce a chemical reaction.

Principle

Fundamental concept or rule that guides the operation of laboratory procedures.

Reagent Preparation

Process of preparing chemical substances used in laboratory tests.

Reagent Storage

Conditions and methods used to keep reagents in usable condition.

Reagent Deterioration

The process by which reagents lose their effectiveness over time.

Expiration Date

The date after which a reagent should not be used.

Precautions

Safety measures taken to prevent accidents or errors in the laboratory.

Specimen Collection and Storage

Methods for obtaining and preserving samples for testing.

Interferences

Substances that can affect the accuracy of test results.

Materials Provided

Items supplied for conducting laboratory tests.

Calibration Parameters

Settings and criteria used to ensure accurate measurements in tests.

Limitations

Constraints or restrictions that affect the validity of test results.

Quality Control

Procedures implemented to ensure the accuracy and reliability of test results.

Reagents

Substances used in chemical reactions for testing purposes.

Documentation/Tracking

Record-keeping practices required by accrediting agencies.

Receive Date

The date on which reagents are received in the laboratory.

Open/Prepare Date

The date on which a reagent is opened or prepared for use.

Unopened expiration vs. Open/On-Board Expiration

Different expiration dates for reagents based on whether they are sealed or in use.

Calibrator

Purchased material used to establish a correlation between the measurement response and the concentration/amount of substance that is being measured.

Calibration Curve

Graphical representation of the relationship between the concentration of a substance and the measurement response.

Quality Controls (QC)

Purchased material with a known concentration of substance(s) used to ensure accurate test results.

Acceptable Range

The range of results specified by the manufacturer that are considered valid.

Proficiency Testing Material

Purchased material from an outside organization used to assess the accuracy of laboratory processes.

Patient Samples

Specimens collected from patients for testing, which have unknown values.

Reference Range

Range of patient values that includes 95% of the test results for a healthy reference population.

Normal Value

A value that falls within the established reference range.

Abnormal Value

A value that falls outside the established reference range.