NxStage Medical Reports First Quarter 20...(c and educational initiatives to ...),Health

educational initiatives to accelerate the Company's efforts to

transform renal therapies in the critical care environment.

-- In January 2008, Medisystems Corporation, the Company's wholly-owned

subsidiary, signed a five-year agreement with DaVita Inc. to continue

to supply DaVita's dialysis centers with MasterGuard and ButtonHole

safety needle sets. Safety needles are essential products used to

access patients' blood during the vast majority of chronic dialysis

therapy treatments. MasterGuard is a leading product in this market

in the United States, and became part of NxStage's product portfolio

through the Company's acquisition of Medisystems in October 2007.

Guidance

For the second quarter 2008, the Company expects revenue to be in the range of $30.5 million to $32.5 million. The Company expects a net loss in the range of $13.5 million to $14.5 million or ($0.37) to ($0.40) per share, based on current shares outstanding. The Company expects an Adjusted EBITDA loss in a range of $7.4 million to $8.2 million for the second quarter of 2008 (see the exhibits for a reconciliation of this non-GAAP measure).

For the full year 2008, NxStage expects revenue to be in the range of $130 million to $135 million. The Company also continues to expect a net loss in the range of $52 million to $56 million or ($1.41) to ($1.52) per share for the full year 2008, based on current shares outstanding. The Company expects an Adjusted EBITDA loss in a range of $28 million to $31 million for the full year of 2008 (see the exhibits for a reconciliation of this non-GAAP measure).

The Company has reduced its projection for the number of its home hemodialysis patients at year end and now expects to end 2008 with 3100 to 3500 patients on the System One(TM).

This release contains non-GAAP financial measures, a reconciliation of the Company's non-GAAP fina
'/>"/>