---
title: "Quest Diagnostics: Business Model"
description: "Quest Diagnostics revenue by business segment from its fiscal 2025 Form 10-K, with each part's share, growth and profitability explained."
canonical: https://www.getswoopr.com/stocks/companies/quest-diagnostics/business-model/
source: "Swoopr Investment: https://www.getswoopr.com"
---

# Quest Diagnostics: Business Model & Revenue Engine

## Direct Answer

Quest Diagnostics reports revenue across 2 business segments in its fiscal 2025 Form 10-K. Diagnostic Information Services Business is the largest, with $10.8 billion of revenue (98% of the total), followed by All Other at $250 million (2%).

## How Does Quest Diagnostics Make Money?

Diagnostic Information Services Business supplies 98% of revenue, so Quest Diagnostics's results move mostly with that one business; the others matter more for diversification than for the headline number. Between fiscal 2024 and 2025, Diagnostic Information Services Business grew fastest (+12.2%) and All Other slowest (-3.1%), so the revenue mix tilts toward Diagnostic Information Services Business while that gap lasts.

| Segment | FY2025 revenue | FY2024 revenue | Share of revenue | Change |
| --- | --- | --- | --- | --- |
| Diagnostic Information Services Business | $10.8 billion | $9.6 billion | 97.7% | 12.2% |
| All Other | $250 million | $258 million | 2.3% | -3.1% |

![Bar chart of Quest Diagnostics revenue by segment for fiscal 2025: Diagnostic Information Services Business 97.7%, All Other 2.3%.](https://www.getswoopr.com/images/charts/quest-diagnostics-business-model-segment-mix.webp)
*Quest Diagnostics revenue by segment as a share of total revenue, from the table above. The largest is highlighted. Select the chart to open it full size.*

## Which Quest Diagnostics Segments Earn the Most?

| Segment | FY2025 segment operating income | Segment margin |
| --- | --- | --- |
| Diagnostic Information Services Business | $1.8 billion | 17.0% |
| All Other | $32 million | 12.8% |

Segment operating income is the profit measure Quest Diagnostics reports to its chief operating decision maker for each segment. It usually leaves out corporate costs that are not allocated to a segment, so the segments usually add up to more than consolidated operating income, and margins are comparable within Quest Diagnostics more safely than against another company.

## What the Segment Figures Do Not Show

The rows above add up to 100% of Quest Diagnostics's reported revenue for fiscal 2025; the difference is intersegment eliminations, corporate revenue or items the company reports outside its segments. Segment definitions are management's choice and change when a company reorganizes, in which case it restates prior years in the next filing, so a multi-year comparison should use the figures from a single filing. Revenue shows where sales come from, not where profit or cash is earned: a small segment can carry most of the margin.

## Where These Numbers Come From

Every figure on this page is a value Quest Diagnostics reported in the segment note and revenue disclosures of its Form 10-K filed February 26, 2026 (accession 0001022079-26-000015), read from the SEC's Financial Statement Data Sets. The prior-year column is the comparative figure from that same filing, so it reflects any restatement for a change in segments. Category names are the company's own XBRL labels, lightly reformatted for reading.

Rows that only total other rows (for example a "Products" line beside the individual products) are left out so nothing is counted twice. This page is educational and describes reported history for fiscal 2025; it is not a forecast or a recommendation.

## Frequently Asked Questions

### What are Quest Diagnostics's business segments?

In its fiscal 2025 Form 10-K, Quest Diagnostics reports revenue for Diagnostic Information Services Business and All Other.

### Which part of Quest Diagnostics brings in the most revenue?

Diagnostic Information Services Business, with $10.8 billion of revenue in fiscal 2025, or 98% of the total.

### Where does Quest Diagnostics report its segment results?

In the segment note to the financial statements in its Form 10-K, most recently filed February 26, 2026, alongside management's discussion of each segment's results.

## References

- [SEC EDGAR: QUEST DIAGNOSTICS INC Form 10-K filed February 26, 2026](https://www.sec.gov/Archives/edgar/data/1022079/000102207926000015/dgx-20251231.htm)
- [SEC EDGAR: QUEST DIAGNOSTICS INC annual and quarterly filings](https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=1022079&type=10-K)
- [SEC: EDGAR application programming interfaces (XBRL frames and submissions data)](https://www.sec.gov/search-filings/edgar-application-programming-interfaces)
- [SEC: Financial Statement Data Sets](https://www.sec.gov/data-research/sec-markets-data/financial-statement-data-sets)

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**[Swoopr Editorial Team](https://www.getswoopr.com/authors/swoopr-editorial-team/)**

Swoopr's editorial team produces independent investment education content reviewed for accuracy and clarity. We do not provide personalized financial advice. See our [editorial policy](https://www.getswoopr.com/legal/editorial-policy/) and [corrections policy](https://www.getswoopr.com/legal/corrections-policy/).