April 29 (Reuters) - Laboratory operator Labcorp LH.N beat analysts' estimate for first-quarter profit on Tuesday, helped by robust demand for its diagnostic tests.

Healthy demand for non-urgent surgeries, especially among older Americans, over the last few quarters has buoyed the demand for diagnostic checkups.

Revenue from its diagnostic laboratories business grew 6% to $2.63 billion during the period, even though it was negatively impacted by adverse weather.

Labcorp and peer Quest Diagnostics DGX.N have also benefited from deals to manage hospital labs as they seek market share gains.

The North Carolina-based company's revenue rose 5.3% to $3.35 billion, but missed analysts' average estimate of $3.40 billion, according to data compiled by LSEG.

Excluding one-off items, it earned $3.84 per share during the quarter ended March 31, compared with the estimate of $3.74 per share.

"While the macroeconomic environment remains dynamic, the critical nature of the work we do in diagnostics and drug development positions us well for success in 2025 and beyond," CEO Adam Schechter said.

"We continue to progress our pipeline of attractive acquisitions and partnerships and further expand our test menu in four strategic areas, including oncology, women's health, autoimmune disease and neurology."

Labcorp raised the lower end of its 2025 adjusted profit forecast to $15.70 from $15.60 per share previously, keeping the upper end unchanged at $16.40 per share.

(Reporting by Puyaan Singh in Bengaluru; Editing by Shilpi Majumdar)

((Puyaan.Singh@thomsonreuters.com))