BCAL Diagnostics (ASX:BDX) BREASTEST Monitor flags 91% sensitivity in early recurrence read

A 95% negative predictive value points at a real surveillance role for post-treatment patients

BCAL Diagnostics (ASX:BDX) has put a second product on the board. The company today unveiled BREASTEST Monitor, a blood test designed to rule out local recurrence of breast cancer in women who have already been treated. The early data shows 91% sensitivity and a 95% negative predictive value across a held-out test set of 100 samples.

That is a meaningful step beyond the company’s first product, BREASTESTplus, which is positioned as a screening adjunct for women with dense breasts. Monitor targets a different patient at a different point in the journey. Specifically, the roughly 200,000 Australian and 4 million US breast cancer survivors who need ongoing surveillance for a recurrence rate that runs as high as 15%.

The market opportunity is real. Mammography misses 25% to 32% of recurrences in this group, with the failure rate climbing in women with dense tissue or post-treatment scarring. A cheap blood test that reliably rules out recurrence would slot neatly into a global surveillance market projected at US$4.5 billion by 2030.

The catch, as always with diagnostics, is the gap between a promising preliminary readout and a commercially launched product.

What the 91% sensitivity number actually tells us

The test was built on 450 samples and then validated on a held-out set of 100, containing 23 confirmed local recurrences and 77 imaging-negative controls. BREASTEST Monitor flagged 20 of the 23 recurrences correctly. That is the source of the 91% sensitivity headline.

The 95% negative predictive value is arguably the more important number for the intended use case. A rule-out test lives or dies on how confidently a negative result can be trusted. At 95%, the model is telling clinicians that a clean test result is highly likely to be a genuinely clean patient.

We would still flag two caveats. The cohort is women aged 50 and above with a known previous breast cancer, and the sample size in the recurrence arm is modest. BCAL has acknowledged this by opening recruitment to women under 50 and committing to further validation studies before commercial launch.

Why the surveillance market is a different beast to screening

Screening tests have to convince a healthy population, and the clinical pathways are crowded. Surveillance is a more contained problem. The patient already has a diagnosis on file, the clinician already has a scheduled follow-up cadence, and the question being asked is narrower.

That changes the commercial pathway. Reimbursement conversations sit with oncology rather than primary care, and the adoption decision usually runs through a smaller group of treating specialists. For a small-cap diagnostic company, that is a more navigable go-to-market than a population screening rollout.

BCAL’s own framing matches this. Monitor will launch as an adjunct to imaging first, with a longer-term ambition to position it as a standalone surveillance test. That second step is where the real value lives, but it is also where the regulatory and clinical evidence bar climbs sharply.

How this fits with the existing BCAL product story

Investors who have followed BCAL through its earlier BREASTESTplus rollout will recognise the playbook. Build a blood-based diagnostic, validate it on dense-breast and other underserved populations, then layer additional indications onto the same platform.

Monitor extends that platform into post-treatment care without requiring a new commercial infrastructure. The same sales channel, the same lab workflows, and broadly the same clinician audience can carry a second product. That is the operating leverage argument for platform diagnostic plays.

It also sits alongside the company’s licensing arrangement with ClearNote Health for the Avantect pancreatic, ovarian and multi-cancer tests across Australia and New Zealand. The broader picture is a small-cap building a cancer diagnostics portfolio rather than betting on a single test.

The Investors Takeaway for BCAL Diagnostics

BREASTEST Monitor is a credible second product, and the early sensitivity and NPV numbers are good enough to take seriously. But this is a preliminary readout on a small recurrence cohort, and the road to a launched, reimbursed surveillance test is paved with larger studies, regulatory submissions and clinical adoption work.

We think investors should focus on three near-term signposts. The recruitment cadence for the under-50 cohort, the timing and design of the next validation study, and any movement on reimbursement conversations once a launch pathway is locked in. Cash runway will matter too, because diagnostic validation rarely runs cheap.

Readers can find our prior coverage and the interview with Executive Chair Jayne Shaw at stocksdownunder for background on how the platform thesis has developed. For now, today’s announcement firms up the case that BCAL is building more than a one-product story.