The Mix Engine in Infectious Disease Diagnostics Stalls at Twenty-Six Per Cent of the Base

Infectious disease diagnostics is the largest application area in in vitro diagnostics and it is slowing down, and the reason is not competition. It is that the mechanism which produced its growth has a ceiling, and the ceiling is now visible in the arithmetic.

The field is USD 30,150 million in 2025 and reaches USD 44,040 million in 2033 — a 4.85% CAGR and USD 13,890 million of absolute growth. Test volume compounds at 5.49%, from 6,000 million tests to 9,200 million. Realised revenue per test therefore falls from USD 5.025 to USD 4.787, a 0.61% annual decline.

Four numbers that explain the whole field

Add the first three and you get the fourth. The field grows its revenue more slowly than its volume, and the gap is priced, not lost.

Now look at what the middle two rows mean together. Constant-menu price falls 2.10% a year. Mix adds 1.49 points. The mix contribution is the entirety of this field’s pricing power — without it, revenue per test would fall at the full 2.10% and the market would be growing at roughly 3.4% rather than 4.85%.

The engine is panelisation, and panelisation has an end state

Mix rises for one reason: a hospital that once ordered a single-target test — influenza, or a stool culture, or a blood culture identification — now orders a panel or a cartridge that costs more per episode. Each conversion raises the average price of a test without any vendor raising a price.

That engine runs only while there are single-target tests left to convert. And the arithmetic of when it stops is already in the segment table.

The two segments that drive mix are 22.29% of the 2025 base and 26.34% of the 2033 base. That is the ceiling, roughly: once syndromic panels and metagenomics reach the mid-twenties as a share of the field, there is no remaining base of single-target tests large enough for conversion to keep adding 1.49 points a year.

When that happens, revenue growth converges on volume growth minus the constant-menu price cut — in the region of 3.2% to 3.5%. Not because the market stops growing in volume, but because it stops being able to charge more per test.

The evidence that the mix is real — and narrow

This is not a modelling artefact. It shows up in disclosed lines, and it shows up unevenly.

bioMérieux is the cleanest case for the mechanism: its microbiology line grew 4% to EUR 1,339 million, while BIOFIRE non-respiratory, the panel attached to that culture, grew 10% to EUR 598 million. The panel grows two and a half times as fast as the culture it sits beside. Its point-of-care molecular platform SPOTFIRE grew 84% — from EUR 168 million, so a small base, but the direction is unambiguous.

Qiagen is the other: diagnostic solutions net sales grew 7% to USD 803.1 million on QuantiFERON and QIAstat-Dx, with more than 5,200 QIAstat-Dx placements. That is the fastest-growing disclosed line in the field, and it is a syndromic panel business.

Against which: Danaher’s diagnostics segment grew 1.5% core and Roche’s diagnostics division 2% at constant exchange rates. The field’s growth is not being carried by the largest players. It is being carried by the two product families whose share is expanding, which is exactly what a mix effect looks like from the inside.

And the base is still resetting underneath it

A mix engine pushing the average up, running on a base that is still contracting from the emergency period, is a field with two contrary forces in it.

Abbott’s COVID-19 testing-related sales fell from USD 747 million in 2024 to USD 297 million in 2025 — a 60.2% decline, USD 450 million of revenue removed from one product family inside one company, two years after the emergency ended. Its Rapid Diagnostics line still fell 18.1% overall, with the United States down 20.8%, while Abbott Point of Care grew 3.1%. The consumer channel deflates; the professional one grows.

That distinction matters for the mix argument, because a decentralised channel in contraction pulls against the panelisation story: panels are a laboratory and physician-office product, and the fastest-shrinking part of the field is the part that was never panelised in the first place.

The two slowest segments are a third of the base

The segments this field grew out of are still the biggest things in it. Serology and immunoassay pathogen detection is 19.57% of the base growing at 3.21%; rapid antigen and point-of-care testing is 14.26% of the base growing at 3.12%. Together the two slowest segments are 33.83% of the 2025 base and 20.88% of the increment. The two fastest — syndromic panels and metagenomics — are 22.29% of the base and 35.13% of the increment.

That shape is identical to the one every discipline report in this cluster has independently produced, and it has the same cause each time: the volume is where the money isn’t. A rapid antigen test is sold for cents and a fifteen-target respiratory panel for tens of dollars, and the first grows in units faster than the second grows in dollars.

What would restart the engine, and what would stall it

Three things could extend the mix runway beyond 26% of the base.

Per-episode pricing. If a panel is paid for as a patient episode rather than per analyte, the pricing question changes from how many targets to how many decisions. That is the one path where laboratory and vendor interests align, because both are currently paid per unit of output rather than per answer.

Metagenomics reaching coverage. It grows at 14.02% and is 1.39% of the base. If reimbursement lands, it is the only segment that could plausibly double the mix engine’s headroom — but it is also priced inside the molecular-pathology family, which the preliminary CY 2027 schedule cuts by 22%.

Antimicrobial-resistance panels tied to stewardship programmes. A susceptibility result that a stewardship team acts on is a different purchase from a pathogen-detection result, and hospital infection-control budgets are not laboratory budgets.

And one thing would stall it quickly: the fee schedule landing in full. The preliminary CY 2027 Medicare rates cut molecular pathology by 22% and microbiology by 19.3% — the two code families in which this entire field’s output is paid. In that case the market lands at USD 41,300 million at 4.02% rather than USD 44,040 million at 4.85%.

The difference between 4.85% and roughly 3.4% is not a forecast error. It is a menu question: whether the field can keep selling a more expensive answer, or only more answers.

Method and disclosure

This analysis is built at a 70% secondary and 30% primary basis. The secondary construction is a bottom-up attribution from company disclosure across thirteen pools totalling USD 17,984 million (59.65%), with a stated residual of USD 12,166 million (40.35%) rather than a distributed one. The primary programme — 38 depth interviews across 11 markets, 24 open-ended interviews through tender and procurement cycles, a 171-respondent laboratory and clinical survey, and four conferences — establishes mechanism only and carries no figure.

“Disclosed” in this piece means a company publishes a line we can use, not that it publishes a pure infectious-disease number. Abbott’s three lines are infectious-disease-dominant but not pure; the allocation from segment to field is ours and is labelled. FX basis EUR 1.13, CHF 1.15 and JPY 148 per USD, matching the rest of this cluster. No third-party market-research material is cited anywhere in this piece.

Sources

• Abbott Laboratories — Fourth-Quarter and Full-Year 2025 Results (22 January 2026)
• bioMérieux — FY2025 results
• QIAGEN N.V. — Form 20-F for the year ended 31 December 2025
• Danaher Corporation — Fourth Quarter and Full Year 2025 Results (28 January 2026)
• Roche — full-year 2025 results
• Centers for Medicare & Medicaid Services — Preliminary CY 2027 Medicare CLFS Payment Rates (21 September 2026)
• WHO Global Tuberculosis Report 2025; GBD 2021 Antimicrobial Resistance Collaborators, The Lancet

Companion reading

• Global Infectious Disease Diagnostics Market, 2026–2033 — the full field this analysis is drawn from, across seven segments and thirteen attributed pools.
• Global Microbiology Diagnostics Market, 2026–2033 — the one discipline in the cluster where realised revenue per test rises, because a culture is being rebilled as a panel.
• Global Haematology and Coagulation Diagnostics Market, 2026–2033 — the mirror image: two fields diverging on price, with revenue per result falling 6.4% in one and rising 12.2% in the other.
• Global In Vitro Diagnostics Market, 2026–2033 — the USD 108.0 billion base against which this field is 27.92%.

Related analysis

• Haemostasis Is Forty-Three Per Cent of This Discipline and Fifty-Seven Per Cent of Its Growth — the inverse case: a field where revenue per test rises 12.21% because the mix shifts toward specialist haemostasis assays, against a haematology field where it falls 6.4%.
• Mindray Grew Share in a Market That Fell Twenty-Three Per Cent — what happens to a diagnostics field when a procurement authority sets the ceiling from what hospitals already paid, and why the price discovered in one province travels.