Capillary blood test for carbon monoxide poisoning

Evaluation of the Accuracy of Capillary Versus Venous CO Measurement in Subjects With Suspected Carbon Monoxide Poisoning: a Prospective, Multicenter, Diagnostic, Controlled Study.

Observational Nantes University Hospital · NCT06641752

This tests whether a small capillary (finger‑stick) blood drop can accurately measure carboxyhemoglobin in adults who come to the emergency department with suspected carbon monoxide poisoning.

Quick facts

Study typeObservational
Enrollment120 (estimated)
Ages18 Years and up
SexAll
SponsorNantes University Hospital Academic / other
Locations2 sites (Angers, Loire-Atlantique and 1 other locations)
Trial IDNCT06641752 on ClinicalTrials.gov

What this trial studies

This observational study compares carboxyhemoglobin (COHb) levels obtained from a capillary (finger‑stick) sample with levels from standard venous or arterial blood in adults presenting to the emergency department with suspected carbon monoxide intoxication. Participation is limited to a brief capillary sampling procedure that takes about 5–15 minutes and does not require additional invasive draws beyond routine clinical care. The primary outcome is the agreement and accuracy of capillary COHb versus venous/arterial COHb measurements. Data are collected at two university hospitals to determine whether capillary sampling could serve as a reliable bedside alternative.

Who should consider this trial

Good fit: Adults who present to the emergency department with symptoms and a history compatible with carbon monoxide exposure and who can give informed consent are the ideal candidates.

Not a fit: Minors, pregnant or breastfeeding women, incarcerated individuals, patients under protective supervision, and anyone who refuses participation are excluded and will not benefit from this protocol.

Why it matters

Potential benefit: If capillary measurements match venous/arterial results, patients could get faster, less invasive bedside COHb results to guide treatment.

How similar studies have performed: Point-of-care CO-oximetry and rapid COHb measurement techniques have shown mixed but promising accuracy, while direct capillary COHb sampling has relatively limited validation in published literature.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Adult patient admitted to emergency department
* Presenting one or more clinical signs (asthenia, headache, nausea, vomiting, loss of consciousness, etc.) and a history compatible with CO intoxication (collective symptoms, notion of smoke, activation of a detector, etc.).

Exclusion Criteria:

* Minors
* Patients under protective supervision (safeguard of justice, curatorship, guardianship)
* Incarcerated patients
* Pregnant or breast-feeding women
* Patients refusing to take part in the study

Where this trial is running

Angers, Loire-Atlantique and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Carbon Monoxide IntoxicationIntoxicationCarbon monoxydeCarboxyhemoglobinCOHbCarboxyhemoglobin capillary
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.