LTP12 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Quality management system hierarchy

Documents are arranged from quality manual through procedures and work instructions to forms and records, with each level traceable to the level above it.

BSL-2 requirements

Moderate-hazard agents require restricted access, biohazard signage, handwashing, a biosafety cabinet for aerosol-generating work, and trained personnel under supervision.

Safety Data Sheet sections

Sixteen standardized sections begin with identification and hazard identification and end with transport and regulatory information; Sections 1 through 8 cover first aid and handling.

Competency assessment timing

Assessment is required before independent testing, after a method or policy change, and at least annually thereafter, using observation and blind sample testing.

Percent error formula

Percent error equals measured minus true value, divided by true value, multiplied by one hundred, expressing the deviation as a percentage.

Skin puncture order of draw

After discarding the first drop, collect EDTA tubes first, then other additive tubes, serum tubes, and heparin last to minimize additive and tissue-fluid contamination.

Citrate tube fill requirement

Citrate tubes must fill to the indicated line to maintain the nine-to-one blood-to-anticoagulant ratio; short draws falsely prolong clotting times.

Hemolysis interference effects

Hemolysis falsely raises potassium, LDH, AST, and phosphate, and may lower glucose or bilirubin depending on the method; significant interference warrants recollection.

Light-sensitive analyte handling

Bilirubin, vitamin B12, folate, and porphyrins degrade with light exposure, so specimens are collected in amber or foil-wrapped tubes and transported protected.

Specimen rejection criteria

Unlabeled or mislabeled containers, gross hemolysis, insufficient volume, expired devices, and unapproved temperature excursions are grounds for rejection and recollection.

Validation versus verification

Validation establishes performance for a new or modified method; verification confirms that a manufacturer's validated method meets claims in the local laboratory.

Precision versus accuracy

Precision is agreement among replicate measurements, expressed as SD or CV; accuracy is agreement with the true value, expressed as bias or recovery.

CV percent formula

CV percent equals the standard deviation divided by the mean, multiplied by one hundred, and is compared against a predefined acceptance limit.

Limit of quantification

The lowest analyte concentration that can be measured with predefined precision and bias goals, typically the lowest point on the validated analytical range.

Linearity evaluation

At least five concentrations spanning the reportable range are tested; deviation from the expected line must fall within the laboratory's stated tolerance.

Westgard 1-3s rule

A single control value exceeding the mean by three standard deviations is a rejection rule indicating random error, requiring run rejection and investigation.

Westgard 2-2s rule

Two consecutive control values exceed the same two-standard-deviation limit, on one or across two materials, indicating systematic error and run rejection.

Westgard 10x rule

Ten consecutive control values fall on the same side of the mean, indicating a systematic shift such as a calibration drift or reagent lot change.

Calibration versus calibration verification

Calibration establishes the signal-to-concentration relationship using calibrators; calibration verification confirms that relationship using independent materials at multiple levels.

Sigma metric formula

Sigma equals the total allowable error minus absolute bias, divided by the CV; higher sigma permits fewer QC rules and lower sigma requires tighter monitoring.

Beer-Lambert law

Absorbance equals molar absorptivity times path length times concentration; photometric measurement is valid only within the linear absorbance region.

Nernst equation application

Ion-selective electrodes relate measured potential to the logarithm of ion activity, so ionic strength and matrix differences affect reported results.

Hook effect

Very high analyte concentrations saturate both capture and detection antibodies in sandwich immunoassays, producing falsely low results that resolve after dilution.

Competitive immunoassay response

Signal is inversely proportional to analyte concentration because labeled and unlabeled analyte compete for limited binding sites; used for small molecules.

Osmolal gap calculation

Measured osmolality minus calculated osmolality from sodium, glucose, and urea; a gap above roughly ten suggests unmeasured osmotically active substances.

Reference interval definition

The central ninety-five percent interval from at least one hundred twenty healthy reference individuals, spanning the 2.5th to 97.5th percentiles.

Delta check purpose

Compares a current result to a prior result from the same patient using an absolute or percentage threshold to flag possible specimen or analytic errors.

Critical value read-back

The receiving person repeats back patient identifier, test name, result, and their own name, and the entire exchange is documented with date and time.

Friedewald calculation limits

LDL cholesterol by Friedewald is invalid when triglycerides exceed about 400 mg/dL or when the patient is not fasting; such results must be suppressed or flagged.

CLIA test complexity categories

Tests are classified as waived, moderate, or high complexity, and the laboratory must hold a certificate matching the highest complexity it performs.

Corrective versus preventive action

Corrective action eliminates the cause of a detected nonconformity; preventive action eliminates the cause of a potential nonconformity before it occurs.

Carryover testing procedure

A high-concentration sample is followed immediately by a low-concentration sample; a positive bias in the low sample indicates carryover requiring wash optimization.