Medical Laboratories Industry Terminology

Accessioning

The process of logging and uniquely identifying a patient specimen upon receipt, assigning an accession number, labeling, and entering order details into the LIS to enable tracking through all phases of testing.

The specimen was accessioned as 25-004321 at 08:12; Accessioning errors caused two mislabeled tubes; We cleared the accessioning backlog before the courier arrived.

Analytical Measurement Range (AMR)

The range of analyte concentrations that an instrument or method can measure directly without dilution, concentration, or other pretreatment, under stated conditions.

The AMR for serum glucose is 10–600 mg/dL; Results above the AMR are diluted and rerun; We verified the AMR during method validation.

Analytical Validation

A structured study to establish test performance (accuracy, precision, analytical sensitivity/specificity, linearity, reportable range, robustness) before clinical use.

The lab completed analytical validation for the new troponin assay; Validation included LoD, LoQ, precision, linearity, and method comparison; We documented acceptance criteria per CLIA and CAP checklists.

Antimicrobial Susceptibility Testing (AST)

Laboratory testing that determines the susceptibility of bacteria or fungi to antimicrobial agents, guiding targeted therapy via MICs, categorical calls (S/I/R), or gradient/disk methods.

AST shows the isolate is susceptible to ceftriaxone; We follow CLSI breakpoints for AST; AST revealed multidrug resistance requiring an ID consult.

Automation (Laboratory Automation)

Use of robotics, conveyor tracks, autoverification, and automated modules (pre-, analytical, post-) to increase throughput, reduce errors, and standardize workflows.

Pre-analytic automation reduced manual aliquoting; The new track connects chemistry and immunoassay analyzers; Automation decreased TAT variability on STAT electrolytes.

Barcoding (Specimen Identification)

Machine-readable labeling (1D/2D) of patients, orders, and specimens to enable accurate identification, tracking, and interface with analyzers and LIS/EHR systems.

We added 2D barcodes to minimize mislabels; Positive patient ID with wristband scanning is mandatory; The analyzer rejected a tube due to unreadable barcode.

CAP (College of American Pathologists)

A laboratory accreditation body and provider of proficiency testing and standards; CAP inspections verify compliance with quality, safety, and regulatory requirements.

The CAP inspector requested our QC review process; We closed two CAP deficiencies with a corrective action plan; CAP accreditation is up for renewal this quarter.

Chain of Custody

Documented control of a specimen’s handling and storage from collection to analysis and reporting, required for forensic, workplace drug testing, and certain legal cases.

Toxicology specimens followed chain-of-custody from collection to reporting; A break in chain-of-custody invalidated the legal test result; We use tamper-evident seals to maintain custody.

CLIA (Clinical Laboratory Improvement Amendments)

US federal regulations that set quality standards for all clinical laboratory testing, including personnel qualifications, QC, PT, and validation, stratified by test complexity.

Our CLIA certificate covers high-complexity testing; CLIA requires biennial inspections; New assays must be verified to meet CLIA standards.

CPT Codes

Current Procedural Terminology codes used to describe medical procedures and laboratory tests for billing and reimbursement.

CMP is billed under CPT 80053; The COVID-19 PCR uses CPT 87635; Incorrect CPT coding led to payer denials last month.

Critical Value

A life-threatening test result that requires urgent clinical notification and documented communication according to laboratory policy.

Potassium of 6.8 mmol/L is a critical value requiring immediate call; We review critical value policies annually; The LIS logs critical value notification time stamps.

Ct Value (Cycle Threshold)

In real-time PCR, the cycle number at which fluorescence crosses a detection threshold; inversely related to target nucleic acid quantity.

A Ct of 18 suggests high viral load; Interpretation notes emphasize that Ct values are semi-quantitative; Ct variation can reflect specimen quality and timing.

Data Integrity and Audit Trail

Assurance that data are complete, consistent, accurate, and traceable throughout their lifecycle, supported by system audit trails capturing creation, modification, and access events.

The audit trail shows who changed the result and when; We follow ALCOA+ principles for data integrity; Audit findings cited gaps in audit trail review.

Delta Check

A QC method that compares a current patient result with previous results to detect significant, unexpected changes suggestive of error or true clinical change.

A hemoglobin delta check flagged a 3 g/dL drop; We set delta check limits based on biological variation; Delta failures trigger repeat testing and investigation.

Diagnostic Stewardship

Coordinated interventions to improve appropriate test ordering, specimen collection, and result interpretation to optimize outcomes and reduce waste and harm.

Implementing C. difficile diagnostic stewardship reduced false positives; Order sets promote targeted testing; Stewardship policies discourage duplicate daily labs.

EHR Integration

Technical and workflow integration between the laboratory information system and the electronic health record for electronic ordering, results delivery, and clinical decision support.

Results now flow from LIS to Epic via HL7; We implemented discrete result mapping into flowsheets; Bi-directional orders and results reduced manual entry errors.

Esoteric Testing

Low-volume, specialized, or highly complex assays often performed in reference laboratories, requiring specialized methods, longer TATs, and premium pricing.

We send out esoteric tests like porphyrins and neuroimmunology panels; Esoteric pricing requires prior authorization; Outreach growth is strongest in esoteric menus.

Fee Schedule (Clinical Laboratory Fee Schedule, CLFS)

A payer’s set payment amounts for laboratory tests; in the US, Medicare’s CLFS establishes national base rates that influence market pricing and reimbursement.

Medicare rates follow the CLFS; PAMA reporting affected our fee schedule; Pricing strategy considers CLFS and payer contracts.

FHIR (Fast Healthcare Interoperability Resources)

A modern, API-driven healthcare data exchange standard enabling resources such as Patient, Order, and Observation to be shared across systems with security and scalability.

We exposed a FHIR Observation endpoint for results; A FHIR-based prior auth workflow is in pilot; Vendor’s LIS roadmap includes FHIR R4 support.

High-Complexity Testing (CLIA)

A CLIA category for tests requiring advanced skills, stringent validation, and specific personnel requirements, including many molecular and microbiology methods.

High-complexity PCR requires specific personnel qualifications; Our competency program meets high-complexity criteria; We maintain separate SOPs by complexity level.

HL7 (Health Level Seven)

A widely used healthcare messaging standard (notably HL7 v2) for exchanging orders, results, and demographic data between the LIS, EHR, and instruments.

Orders flow via HL7 ORM messages; Results transmit as ORU^R01; Interface tickets tracked HL7 segment mapping issues.

Immunoassay

An assay using antigen-antibody binding to detect or quantify analytes; platforms include CLIA, ECL, lateral flow, and automated analyzers.

Our troponin is a chemiluminescent immunoassay; Heterophile antibodies can cause immunoassay interference; We verified cross-reactivity claims for the testosterone immunoassay.

Interference and Cross-reactivity

Effects from substances or structurally related molecules that skew results, including endogenous (hemolysis, lipemia, icterus) or exogenous (biotin, drugs) interferences.

Biotin interference caused falsely low TSH; Hemolysis interfered with potassium results; The assay shows 5% cross-reactivity with structurally similar steroids.

Internal Quality Control (IQC)

Routine monitoring of assay performance using control materials to ensure stability and detect errors before releasing patient results.

Daily IQC uses two levels with Westgard rules; QC shifts triggered lot-to-lot comparison; We plot QC on Levey–Jennings charts.

Laboratory Developed Test (LDT)

An in-house designed and validated test performed by a clinical laboratory, currently regulated under CLIA with evolving federal oversight frameworks.

Our ctDNA LDT underwent rigorous validation; We updated LDT documentation ahead of inspection; FDA oversight of LDTs is evolving.

Laboratory Information System (LIS)

Core informatics platform for order entry, specimen tracking, QC, result reporting, interfaces, and regulatory documentation in the laboratory.

The LIS autoverifies normal CBCs; We implemented middleware rules in the LIS; Downtime procedures cover manual entry and delayed interfacing.

Levey–Jennings Chart

A control chart plotting QC results over time against mean and SD limits to visualize assay stability and detect systematic or random errors.

The QC is trending upward on the LJ plot; She reviewed the last month’s LJ charts for shifts; An out-of-control LJ point triggered troubleshooting.

Limit of Detection (LoD)

The lowest analyte level that can be reliably distinguished from background noise under stated conditions, though not necessarily quantified with acceptable precision.

The SARS-CoV-2 assay LoD is 250 copies/mL; We confirmed LoD using a 20-replicate study; Marketing materials must reflect the validated LoD.

Limit of Quantitation (LoQ)

The lowest analyte concentration that can be quantified with acceptable precision and accuracy, as defined by validation criteria.

LoQ was established at 0.02 ng/mL for troponin; Results below LoQ are reported as less than; We verified LoQ precision at the decision point.

LOINC (Logical Observation Identifiers Names and Codes)

A universal coding system for lab tests and clinical observations that supports semantic interoperability across systems and organizations.

Hemoglobin result maps to LOINC 718-7; We expanded LOINC mapping for interoperability; Clients require LOINC codes on outbound interfaces.

MALDI-TOF MS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry used for rapid identification of microorganisms and other analytes based on protein spectra.

MALDI-TOF identified E. coli in minutes; We updated the MALDI-TOF library monthly; MALDI-TOF reduced time to organism ID by 24 hours.

Next-Generation Sequencing (NGS)

High-throughput sequencing technologies enabling parallel analysis of many genomic regions for applications such as oncology, hereditary disease, and infectious disease.

The oncology NGS panel targets 500 genes; Coverage depth and uniformity met QC thresholds; NGS variants are confirmed by orthogonal methods when needed.

Outreach Testing (Laboratory Outreach Program)

A business model where a hospital or independent lab sells testing services to external clients (physician offices, clinics), requiring client services, logistics, and contracting.

Outreach grew 12% year-over-year; Couriers and remote phlebotomy support outreach clients; Outreach pricing reflects payer mix and logistics costs.

PAMA (Protecting Access to Medicare Act)

US law that ties Medicare CLFS reimbursement to market-based private payer rates, reshaping laboratory pricing and revenue.

PAMA cuts lowered CLFS rates for core chemistry; We completed PAMA private payer data reporting; PAMA materially affects outreach margins.

Payer Mix

The proportion of laboratory volume or revenue by payer type; a key driver of average reimbursement and margin.

Our payer mix is 45% Medicare, 15% Medicaid, 35% commercial, 5% self-pay; Shifts in payer mix impacted net collections; Outreach business improves commercial payer mix.

Pre-analytical Phase

All steps prior to analysis, including test ordering, patient identification, specimen collection, handling, transport, and preparation, which heavily influence result quality.

Most errors occur pre-analytically during collection and transport; We implemented pneumatic tube restrictions for certain assays; Cold-chain lapses compromised specimens.

Prior Authorization

Payer requirement to obtain approval before performing certain tests, especially high-cost or genetic assays, to ensure medical necessity and payment.

Prior auth is required for genetic panels; Lack of prior auth led to denials; We automated prior auth checks in the ordering workflow.

Proficiency Testing (PT)

External assessment of laboratory performance by testing unknown specimens from an approved provider and comparing results against peers or targets.

CAP PT samples were tested like patient specimens; A PT failure triggered a root cause analysis; We maintain PT records for inspections.

Quality Assurance (QA)

A comprehensive quality program encompassing policies, audits, training, document control, incident management, and continuous improvement across all lab processes.

QA reviews include audits, document control, and nonconformance tracking; We opened a corrective action after an audit finding; QA monitors TAT and specimen rejection KPIs.

Reference Range

The interval of expected values for a defined healthy population, often partitioned by age and sex, used to interpret individual test results.

Pediatric reference ranges differ from adult ranges; We validated reference ranges for our population; Reports show both patient result and reference interval.

Reflex Testing

Automatic follow-up testing triggered by predefined rules based on initial results to improve clinical utility and efficiency.

TSH reflexes to free T4 when abnormal; Positive HIV screens reflex to confirmatory testing; Micro reflex algorithms reduce unnecessary cultures.

Reimbursement

Payment received from payers for laboratory services, shaped by fee schedules, contracts, medical necessity, coding, and utilization controls.

Net collections improved after contract renegotiations; Payers reimbursed below CLFS for some send-outs; Denial management increased realized reimbursement.

Send-out Testing

Tests referred to external reference laboratories due to complexity, volume, or economics, managed via send-out logs, contracts, and logistics.

We send out esoteric immunology to a reference lab; Send-out costs require careful markup and payer alignment; Courier schedules drive send-out cutoffs.

Sensitivity and Specificity

Performance measures of a test’s ability to correctly identify disease (sensitivity) and non-disease (specificity); inform PPV/NPV and clinical utility.

The assay sensitivity is 98% and specificity is 99%; We explained PPV depends on disease prevalence; Validation compared sensitivity to the gold standard.

STAT Testing

Tests designated for urgent, time-critical processing and reporting with expedited workflows and defined turnaround targets.

STAT troponin TAT target is 45 minutes; The LIS prioritizes STAT orders in analyzer queues; Excess STAT labels can degrade routine TAT.

Test Menu

A catalog of available laboratory tests including methodology, specimen requirements, TAT, CPT codes, and pricing, used for operations and client communication.

We rationalized the test menu to reduce redundancy; The menu lists methodologies and TATs for clients; New test additions go through a menu committee.

Turnaround Time (TAT)

Elapsed time from a defined starting point (order or receipt) to result reporting; a key performance and service metric.

Chemistry median TAT improved to 60 minutes; Contracts stipulate TAT SLAs for outreach clients; We track TAT by phase to target bottlenecks.

Utilization Management

Systematic efforts to ensure appropriate test ordering and frequency, aligning with evidence, reducing waste, and improving value.

A rules engine blocks duplicate orders within 24 hours; UM reduced daily labs in stable inpatients; We review high-cost test utilization monthly.

Value-Based Care

Healthcare models that reward outcomes and efficiency rather than test volume, requiring labs to demonstrate clinical impact and cost avoidance.

Lab data supports value-based care pathways; We quantify how testing reduces admissions; Payers tie incentives to outcomes, not volume.

Westgard Rules

A set of statistical QC decision rules applied to control data (e.g., 1-2s, 1-3s, 2-2s) to detect random and systematic errors before releasing results.

A 1-3s violation halted patient reporting; We trained staff on multirule Westgard application; Rules were tuned to the assay’s sigma performance.