With more than 374 S&P 500 members having reported their Q1 results, there is some guaranteed good news for investors keen on the Medical sector. As per our latest Earnings Trends report, among the 16 basic Zacks sectors, only 7 have been predicted to report positive year-over-year growth. Medical is one of them.So far, more than 75% of the Medical sector index members have released their first-quarter financial numbers, out of which 80% have reported better-than-expected earnings performance on revenue beat of 70%. Accordingly, earnings were up 8.8% year over year on an 11.2% revenue growth rate.The Medical Instrument subsector, an integral part of the entire Medical space, is no way an exception to the broader sector’s uptrend, thanks to the temporary repeal of the controversial MedTech tax. We note that all the S&P members from this subsector who have already reported their first-quarter results, registered better-than-expected earnings.In the upcoming week too, some popular names in the Medical Instruments space are warming up for their releases. Let’s see what’s in the cards for these companies.Penumbra, Inc. PEN, a global interventional therapies company that went public on Sep 17, 2015, is expected to report its first-quarter 2016 financial numbers on May 9, after the market closes. Penumbra has an Earnings ESP of 0.00% and a Zacks Rank #3 (Hold).Inogen Inc. INGN, a provider of innovative respiratory products for use in the homecare setting, is scheduled to report first-quarter 2016 results on May 9. Inogen’s unique direct-to-customer business model, innovative product portfolio and growing patient base are currently at investors’ focus. Inogen currently has a -8.33% ESP and a Zacks Rank #2 (Buy).Opko Health, Inc. OPK is a diversified healthcare company with a diagnostics business that includes Bio-Reference Laboratories, the nation’s third-largest clinical laboratory with a core genetic testing business. Opko Health is also slated to release its first-quarter 2016 financial numbers on May 9. The company has an Earnings ESP of 0.00% and a Zacks Rank #3.Another medical instrument company, Nevro Corp. NVRO, a global provider of innovative evidence-based solutions for the treatment of chronic pain, will release its first-quarter 2016 financial numbers on the same date as the above three. The stock carries a Zacks Rank #2, with an Earnings ESP of 0.00%.However, we note that our proven model does not conclusively show that all the four abovementioned Medical Instruments stocks are likely to beat earnings this quarter. This is because a stock needs to have both a positive Earnings ESP and a Zacks Rank #1 (Strong Buy), 2 or 3 for this to happen. That is not the case here as you can see.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report OPKO HEALTH INC (OPK): Free Stock Analysis Report INOGEN INC (INGN): Free Stock Analysis Report PENUMBRA INC (PEN): Free Stock Analysis Report NEVRO CORP (NVRO): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research