A Half-LLOQ Check Was Not the Same as Independently Determining Every Detection Limit
The neonatal cannabinoid study explicitly stated that each analyte’s detection limit was not specifically determined. It checked performance at half the lower quantification limit instead.
The validation described what was actually tested
The researchers verified relevant acceptance criteria and a signal-to-noise ratio of at least three at concentrations equivalent to half the LLOQ. Quantification at the LLOQ required more demanding criteria, including accuracy, imprecision and chromatographic identification requirements.
A tested concentration does not locate the exact boundary
Showing acceptable behavior at one low concentration is useful. It does not establish the precise lowest concentration at which detection would remain reliable under every condition. The half-LLOQ value should therefore not silently become a separately estimated universal LOD.
Reporting categories need their definitions
Detection, numerical quantification and clinical interpretation are distinct. A low analytical signal does not automatically support a precise concentration, exposure date or prognosis. The paper’s paired meconium and cord methods also had different measurement ranges. Retaining the actual validation description allows a fair assessment without exaggerating sensitivity or dismissing useful evidence. The supported claim concerns demonstrated low-level performance under the specified protocol, rather than an independently established minimum for every target and specimen.
Related analysis: the study’s broader findings and limitations.
