The end of the earnings season is always a good time to take a step back and see who shined (and who not so much). Let’s take a look at how testing & diagnostics services stocks fared in Q4, starting with Labcorp (NYSE: LH).

The testing and diagnostics services industry plays a crucial role in disease detection, monitoring, and prevention, serving hospitals, clinics, and individual consumers. This sector benefits from stable demand, driven by an aging population, increased prevalence of chronic diseases, and growing awareness of preventive healthcare. Recurring revenue streams come from routine screenings, lab tests, and diagnostic imaging, with reimbursement from Medicare, Medicaid, private insurance, and out-of-pocket payments. However, the industry faces challenges such as pricing pressures, regulatory compliance, and the need for continuous investment in new testing technologies. Looking ahead, industry tailwinds include the expansion of personalized medicine, increased adoption of at-home and rapid diagnostic tests, and advancements in AI-driven diagnostics that enhance accuracy and efficiency. However, headwinds such as reimbursement uncertainties, competition from decentralized testing solutions, and regulatory scrutiny over test validity and cost-effectiveness may impact profitability. Adapting to evolving healthcare models and integrating automation will be key for sustaining growth and maintaining operational efficiency.

The 5 testing & diagnostics services stocks we track reported a strong Q4. As a group, revenues beat analysts’ consensus estimates by 2.1%.

Amidst this news, share prices of the companies have had a rough stretch. On average, they are down 10.7% since the latest earnings results.

Weakest Q4: Labcorp (NYSE: LH)

With over 600 million tests performed annually and involvement in 90% of FDA-approved drugs in 2023, Labcorp (NYSE: LH) provides laboratory testing services and drug development solutions to doctors, hospitals, pharmaceutical companies, and patients worldwide.

Labcorp reported revenues of $3.52 billion, up 5.6% year on year. This print fell short of analysts’ expectations by 1.4%. Overall, it was a mixed quarter for the company with an impressive beat of analysts’ full-year EPS guidance estimates but a slight miss of analysts’ revenue estimates.

"In 2025, Labcorp grew revenue over 7% and delivered double-digit adjusted EPS growth, margin expansion and strong free cash flow. Performance was driven by continued strength in our Diagnostics and Central Laboratory businesses," said Adam Schechter, Chairman and CEO of Labcorp.

Labcorp scored the highest full-year guidance raise but had the weakest performance against analyst estimates and weakest performance against analyst estimates of the whole group. Still, the market seems discontent with the results. The stock is down 14.2% since reporting and currently trades at $264.15.

Read our full report on Labcorp here, it’s free.

Best Q4: RadNet (NASDAQ: RDNT)

With over 350 imaging facilities across seven states and a growing artificial intelligence division, RadNet (NASDAQ: RDNT) operates a network of outpatient diagnostic imaging centers across the United States, offering services like MRI, CT scans, PET scans, mammography, and X-rays.

RadNet reported revenues of $547.7 million, up 14.8% year on year, outperforming analysts’ expectations by 5.8%. The business had an exceptional quarter with an impressive beat of analysts’ revenue estimates and a beat of analysts’ EPS estimates.

RadNet delivered the biggest analyst estimates beat among its peers. Although it had a fine quarter compared its peers, the market seems unhappy with the results as the stock is down 14.2% since reporting. It currently trades at $59.89.

Is now the time to buy RadNet? Access our full analysis of the earnings results here, it’s free.

Guardant Health (NASDAQ: GH)

Pioneering the field of "liquid biopsy" with technology that can identify cancer-specific genetic mutations from a simple blood draw, Guardant Health (NASDAQ: GH) develops blood tests that detect and monitor cancer by analyzing tumor DNA in the bloodstream, helping doctors make treatment decisions without invasive biopsies.

Guardant Health reported revenues of $281.3 million, up 39.4% year on year, exceeding analysts’ expectations by 3.5%. It may have had the worst quarter among its peers, but its results were still good as it also locked in full-year revenue guidance beating analysts’ expectations and a solid beat of analysts’ revenue estimates.

Guardant Health delivered the fastest revenue growth but had the weakest full-year guidance update in the group. As expected, the stock is down 14.7% since the results and currently trades at $90.78.

Read our full analysis of Guardant Health’s results here.

NeoGenomics (NASDAQ: NEO)

Operating a network of CAP-accredited and CLIA-certified laboratories across the United States and United Kingdom, NeoGenomics (NASDAQ: NEO) provides specialized cancer diagnostic testing services, including genetic analysis, molecular testing, and pathology consultation for oncologists and healthcare providers.

NeoGenomics reported revenues of $190.2 million, up 10.6% year on year. This result surpassed analysts’ expectations by 1%. It was a strong quarter as it also logged a beat of analysts’ EPS estimates and a solid beat of analysts’ full-year EPS guidance estimates.

The stock is down 16.1% since reporting and currently trades at $9.32.

Read our full, actionable report on NeoGenomics here, it’s free.

Quest (NYSE: DGX)

Processing approximately one-third of the adult U.S. population's lab tests annually, Quest Diagnostics (NYSE: DGX) provides laboratory testing and diagnostic information services to patients, physicians, hospitals, and other healthcare providers across the United States.

Quest reported revenues of $2.81 billion, up 7.1% year on year. This number beat analysts’ expectations by 1.9%. Overall, it was a very strong quarter as it also recorded full-year revenue guidance exceeding analysts’ expectations and a decent beat of analysts’ revenue estimates.

The stock is up 3.4% since reporting and currently trades at $197.70.

Read our full, actionable report on Quest here, it’s free.

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