Inogen (INGN Quick QuoteINGN - Free Report) shares soared 5.1% in the last trading session to close at $27.82. The move was backed by solid volume with far more shares changing hands than in a normal session. This compares to the stock's 9.5% gain over the past four weeks.

The stock has risen most probably on the back of anticipation for an improved second quarter results, scheduled to be announced on Aug 4.

This produces oxygen concentrators for patients suffering from chronic respiratory conditions is expected to post quarterly loss of $0.40 per share in its upcoming report, which represents a year-over-year change of -281.8%. Revenues are expected to be $100.74 million, down 0.8% from the year-ago quarter.

Earnings and revenue growth expectations certainly give a good sense of the potential strength in a stock, but empirical research shows that trends in earnings estimate revisions are strongly correlated with near-term stock price movements.

For Inogen, the consensus EPS estimate for the quarter has been revised 5.6% lower over the last 30 days to the current level. And a negative trend in earnings estimate revisions doesn't usually translate into price appreciation. So, make sure to keep an eye on INGN going forward to see if this recent jump can turn into more strength down the road.

The stock currently carries a Zacks Rank #3 (Hold). You can see the complete list of today's Zacks Rank #1 (Strong Buy) stocks here >>>>

Inogen belongs to the Zacks Medical - Instruments industry. Another stock from the same industry, Pacific Biosciences of California (PACB Quick QuotePACB - Free Report) , closed the last trading session 2.7% lower at $4.37. Over the past month, PACB has returned 1.6%.

Pacific Biosciences' consensus EPS estimate for the upcoming report has remained unchanged over the past month at -$0.34. Compared to the company's year-ago EPS, this represents a change of -61.9%. Pacific Biosciences currently boasts a Zacks Rank of #2 (Buy).