LAWRENCE, Mass.

Medical device maker NxStage Medical Inc. said Tuesday its first-quarter loss narrowed as revenue climbed on growing adoption of its NxStage System One home kidney dialysis system.

The Lawrence, Mass., company lost $5.1 million, or 9 cents per share, in the three months that ended March 31. That compares to a loss of $6 million, or 11 cents per share, in the previous year's quarter.

Revenue climbed about 13 percent to $57 million.

Analysts surveyed by FactSet expected, on average, a loss of 10 cents per share on $56.4 million in revenue.

Revenue from the System One home segment, which allows patients to administer their own dialysis, climbed 13 percent to $29.6 million in the quarter.

The company's operating expenses also climbed 10 percent in the quarter to nearly $25 million.

NxStage also said Tuesday that Asahi Kasei Medical Co. Ltd. has converted all of the $45.2 million in outstanding debt and accrued interest owed to it by NxStage into an unspecified number of newly issued common shares of NxStage at a price of $18.41 per share. Asahi Kasei now owns about a 4 percent stake in NxStage, said Kristen Sheppard, NxStage vice president of investor relations.

The companies are collaborating to expand NxStage's System One business in Japan.

NxStage shares fell 3.3 percent, or 55 cents, to $16.24 in afternoon trading, while the Nasdaq exchange dropped about 1 percent.

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