New screening tests: blood, breath and eye

What do the published figures show for blood, breath and eye-based screening tests, and how far have they been tested in people?

Three screening approaches use different samples and measure different things, so their figures cannot be compared directly. The blood test figures come from a trial that missed its primary endpoint, and the breath and lens figures come from smaller or earlier-stage work.

New screening tests: blood, breath and eye. Each cell shows a value, how well it is evidenced, and its sources.
Option	What it screens forThe condition or signal the test is designed to detect. No units.	Published accuracySensitivity (%), specificity (%), PPV (%) or correlation (r), with the study, year, setting and conditions. Figures are not directly comparable across studies.	Regulatory statusAuthorisation or review status as stated in the cited sources, with the date where given.	Main limitationThe most important limit on use, as stated in the cited sources.
Multi-cancer blood tests	One blood sample screened for many cancer types. NHS-Galleri covered 12 prespecified cancers in participants aged 50 to 77 in England.Demonstrated[1]	NHS-Galleri, 2026, company-reported. Across the 12 prespecified cancers, 54.7% episode sensitivity (cancers diagnosed within 12 months of a blood draw). Across all cancers, 99.55% specificity and 52.0% PPV. Not yet peer reviewed.Reported, unverified[1]	Not cleared or approved. On 29 January 2026, GRAIL announced it had submitted the final module of its premarket approval application to the FDA. The FDA designated the test a Breakthrough Device in 2018.Demonstrated[2]	NHS-Galleri did not meet its primary endpoint: combined Stage III and IV diagnoses in the 12 cancers, IRR 1.03 (95% CI 0.92 to 1.14). The results have not yet been published in a peer-reviewed journal.Demonstrated[1]
Breath tests	Breath signatures for cancer detection. The UK PAN Cancer trial is recruiting people with oesophageal and stomach cancer, and plans to add liver, prostate, kidney, bladder and pancreatic cancers.Demonstrated[3]	No reliable public figure	No clearance found in the sources read. On 30 September 2024, Owlstone announced a five-year research collaboration with the FDA's Center for Devices and Radiological Health. The agreement is not a clearance.Demonstrated[4]	The October 2024 article reports no PAN Cancer results. Lung cancer is not among the listed target cancers.Demonstrated[3]
Smart contact lenses	Triggerfish detects changes in eye volume over 24 hours, rather than measuring eye pressure directly. It is indicated for adults aged 22 and over. Tear glucose sensing is research-stage.Demonstrated[5][7]	Tear glucose study, 2024, 10 healthy and 10 diabetic participants over five days (days 1, 3 and 5). Each individual's Pearson correlation with blood glucose was above 0.9, using a personalised time lag. Representative participants: r = 0.97 (healthy) and 0.95 (diabetic).Demonstrated[7]	FDA permission to market, reported in an article dated 7 March 2016. The permission date is not stated in the source. Indicated for adults aged 22 and older, under the direction and supervision of a health care professional.Demonstrated[5]	Output is in arbitrary units (a.u.), not mmHg. Day-to-day reproducibility was r = 0.59 overall (P = 0.117) and r = 0.40 for daytime periods, in 36 patients with glaucoma or suspected glaucoma. The sponsor, Sensimed AG, took part in study design.Demonstrated[6]

New screening tests: blood, breath and eye. Each cell shows a value, how well it is evidenced, and its sources.

Option

What it screens forThe condition or signal the test is designed to detect. No units.

Published accuracySensitivity (%), specificity (%), PPV (%) or correlation (r), with the study, year, setting and conditions. Figures are not directly comparable across studies.

Regulatory statusAuthorisation or review status as stated in the cited sources, with the date where given.

Main limitationThe most important limit on use, as stated in the cited sources.

Multi-cancer blood tests

One blood sample screened for many cancer types. NHS-Galleri covered 12 prespecified cancers in participants aged 50 to 77 in England.Demonstrated[1]

NHS-Galleri, 2026, company-reported. Across the 12 prespecified cancers, 54.7% episode sensitivity (cancers diagnosed within 12 months of a blood draw). Across all cancers, 99.55% specificity and 52.0% PPV. Not yet peer reviewed.Reported, unverified[1]

Not cleared or approved. On 29 January 2026, GRAIL announced it had submitted the final module of its premarket approval application to the FDA. The FDA designated the test a Breakthrough Device in 2018.Demonstrated[2]

NHS-Galleri did not meet its primary endpoint: combined Stage III and IV diagnoses in the 12 cancers, IRR 1.03 (95% CI 0.92 to 1.14). The results have not yet been published in a peer-reviewed journal.Demonstrated[1]

Breath tests

Breath signatures for cancer detection. The UK PAN Cancer trial is recruiting people with oesophageal and stomach cancer, and plans to add liver, prostate, kidney, bladder and pancreatic cancers.Demonstrated[3]

No reliable public figure

No clearance found in the sources read. On 30 September 2024, Owlstone announced a five-year research collaboration with the FDA's Center for Devices and Radiological Health. The agreement is not a clearance.Demonstrated[4]

The October 2024 article reports no PAN Cancer results. Lung cancer is not among the listed target cancers.Demonstrated[3]

Smart contact lenses

Triggerfish detects changes in eye volume over 24 hours, rather than measuring eye pressure directly. It is indicated for adults aged 22 and over. Tear glucose sensing is research-stage.Demonstrated[5][7]

Tear glucose study, 2024, 10 healthy and 10 diabetic participants over five days (days 1, 3 and 5). Each individual's Pearson correlation with blood glucose was above 0.9, using a personalised time lag. Representative participants: r = 0.97 (healthy) and 0.95 (diabetic).Demonstrated[7]

FDA permission to market, reported in an article dated 7 March 2016. The permission date is not stated in the source. Indicated for adults aged 22 and older, under the direction and supervision of a health care professional.Demonstrated[5]

Output is in arbitrary units (a.u.), not mmHg. Day-to-day reproducibility was r = 0.59 overall (P = 0.117) and r = 0.40 for daytime periods, in 36 patients with glaucoma or suspected glaucoma. The sponsor, Sensimed AG, took part in study design.Demonstrated[6]

What the table shows

NHS-Galleri reported 54.7% episode sensitivity across 12 prespecified cancers, and its primary endpoint was not met (IRR 1.03).
No breath test accuracy figure is recorded here, and PAN Cancer reported no results in its October 2024 article.
Triggerfish measures changes in eye volume rather than pressure directly, and is indicated for adults aged 22 and over.
The tear glucose figures come from a study of 20 people, and the blood test is under FDA review, not authorised.

Read with care

Most figures come from company releases, trade press and small pilot studies. The NHS-Galleri results had not been published in a peer-reviewed journal at the time of the cited release.
The measures differ: sensitivity, specificity and PPV for the blood test, correlation for the lens glucose study, and no accuracy figure for breath tests. Trial populations and test versions also differ, so cells should not be compared directly.
No breath test accuracy figure is recorded, because no breath study with accuracy data is cited in this comparison.
The NHS-Galleri sensitivity counts cancers diagnosed within 12 months of a blood draw, so it is not a measure of sensitivity over a full screening programme.

Sources

company announcement
GRAIL Reports Full Results from NHS-Galleri Trial Demonstrating Substantial Reduction in Stage IV Cancer Diagnoses at 2026 ASCO Annual Meeting
GRAIL, 30 May 2026. Accessed 21 Oct 2026.
company announcement
GRAIL Submits FDA Premarket Approval Application for the Galleri Multi-Cancer Early Detection Test
GRAIL, 29 Jan 2026. Accessed 21 Oct 2026.
news
Can a simple breath test detect cancer?
NIHR Cambridge Biomedical Research Centre, 16 Oct 2024. Accessed 21 Oct 2026.
company announcement
Owlstone Medical Enters into a Research Collaboration Agreement with the FDA to Support the Confident Identification of Volatile Organic Compounds on Breath and Expansion of its Breath Biopsy VOC Atlas
Owlstone Medical, 30 Sept 2024. Accessed 21 Oct 2026.
news
FDA permits marketing of Sensimed's Triggerfish
startupticker.ch, 7 Mar 2016. Accessed 21 Oct 2026.
peer reviewed paper
Continuous 24-hour Intraocular Pressure Monitoring With a Contact Lens Sensor: Safety, Tolerability, and Reproducibility in Glaucoma Patients
Mansouri K, Medeiros FA, Tafreshi A et al.. Archives of Ophthalmology, Dec 2012. Accessed 21 Oct 2026.
peer reviewed paper
In-depth correlation analysis between tear glucose and blood glucose using a wireless smart contact lens
Wonjung Park, Hunkyu Seo, Jeongho Kim. Nature Communications, 2 Apr 2024. Accessed 21 Oct 2026.