LoD is the lowest concentration distinguishable from a blank with stated probability. LoQ is the lowest concentration that can be quantitatively measured with stated accuracy and precision (per CLSI EP17 / EP05). CLSI EP17 describes how to establish the limit of blank, LoD and LoQ using replicate testing across lots, instruments and days. The LoQ is often set where total error or imprecision meets a predefined goal. These values appear in the IFU and in performance evaluation evidence under IVDR and in FDA submissions, and matter most for assays used near clinical decision thresholds.

Why it matters

Critical performance characteristics for IVD claims, especially for infectious disease and oncology assays where low-burden detection drives clinical utility.

Common pitfalls

•Failing to establish LoD and LoQ using appropriate statistical methods can lead to invalid claims regarding assay sensitivity.
•Not re-evaluating LoD and LoQ after significant assay modifications can result in underperforming or non-compliant devices.
•Confusing LoD with clinical sensitivity can lead to misinterpretation of an assay's true diagnostic capability.
•Using inappropriate sample matrices for LoD and LoQ studies can invalidate the relevance of the established limits to real-world clinical use.
•Presenting a single LoD or LoQ value when different matrices or sample types require distinct limits is a common oversight.

Sources

CLSI EP17 · CLSI
ISO 14155 Standard Page · ISO
FDA - Clinical Trials and Human Subject Protection · FDA

Open full page

Select term B to compare.

Why compare MedTech terms side by side?

MedTech terminology is full of pairs that look interchangeable but carry very different regulatory, clinical, and commercial consequences. Picking the wrong framework, pathway, or standard early in a project can add months to a submission, invalidate clinical evidence, or trigger an audit finding. Side-by-side comparison is the fastest way to surface those differences before they become costly mistakes.

Each comparison on this page pulls from the same vendor-neutral, sourced definitions used throughout the MedTech Terms glossary. You see the one-line summary, the formal definition, why it matters in practice, common pitfalls, and the primary sources (FDA guidance, EU MDR/IVDR articles, ISO/IEC standards, MDCG documents, IMDRF principles) that back each entry. That makes the comparison defensible in regulatory strategy memos, design reviews, and submission narratives.

Common comparison patterns

Regulatory pathway choice - 510(k) vs PMA, 510(k) vs De Novo, Abbreviated vs Special 510(k).
Quality systems - QSR vs ISO 13485, QMSR vs QSR.
Software classification - SaMD vs SiMD, Locked vs adaptive AI.
EU frameworks - MDR vs IVDR, CE Mark vs UKCA.
Cybersecurity artifacts - SPDX vs CycloneDX SBOM, CVE vs CVSS.
Post-market actions - Recall vs field action, Removal vs correction.

How to use this tool

Pick term A and term B from the dropdowns, or click a preset above. The URL updates with both slugs so you can bookmark or share the exact comparison with a colleague, a notified body reviewer, or your regulatory consultant. Click Open full page on either side for the complete entry, including FAQs, related terms, and the full citation list. If you are not sure which term to start with, browse the Categories view or the A-Z index.

MedTech Terms is a vendor-neutral community resource sponsored by Blue Goat Cyber. Definitions are written for educational use and are not legal or regulatory advice.