For those looking to find strong Medical stocks, it is prudent to search for companies in the group that are outperforming their peers. Has GlaxoSmithKline (GSK) been one of those stocks this year? By taking a look at the stock's year-to-date performance in comparison to its Medical peers, we might be able to answer that question.GlaxoSmithKline is one of 1117 individual stocks in the Medical sector. Collectively, these companies sit at #11 in the Zacks Sector Rank. The Zacks Sector Rank gauges the strength of our 16 individual sector groups by measuring the average Zacks Rank of the individual stocks within the groups.The Zacks Rank is a proven system that emphasizes earnings estimates and estimate revisions, highlighting a variety of stocks that are displaying the right characteristics to beat the market over the next one to three months. GlaxoSmithKline is currently sporting a Zacks Rank of #2 (Buy).Over the past three months, the Zacks Consensus Estimate for GSK's full-year earnings has moved 10.3% higher. This signals that analyst sentiment is improving and the stock's earnings outlook is more positive.Based on the latest available data, GSK has gained about 13% so far this year. At the same time, Medical stocks have lost an average of 7.7%. This shows that GlaxoSmithKline is outperforming its peers so far this year.Omnicell (OMCL) is another Medical stock that has outperformed the sector so far this year. Since the beginning of the year, the stock has returned 49.8%.The consensus estimate for Omnicell's current year EPS has increased 4% over the past three months. The stock currently has a Zacks Rank #2 (Buy).To break things down more, GlaxoSmithKline belongs to the Large Cap Pharmaceuticals industry, a group that includes 14 individual companies and currently sits at #104 in the Zacks Industry Rank. Stocks in this group have gained about 18% so far this year, so GSK is slightly underperforming its industry this group in terms of year-to-date returns.In contrast, Omnicell falls under the Medical Info Systems industry. Currently, this industry has 43 stocks and is ranked #147. Since the beginning of the year, the industry has moved -40.5%.Investors with an interest in Medical stocks should continue to track GlaxoSmithKline and Omnicell. These stocks will be looking to continue their solid performance. Breakout Biotech Stocks with Triple-Digit Profit Potential The biotech sector is projected to surge beyond $2.4 trillion by 2028 as scientists develop treatments for thousands of diseases. They’re also finding ways to edit the human genome to literally erase our vulnerability to these diseases. Zacks has just released Century of Biology: 7 Biotech Stocks to Buy Right Now to help investors profit from 7 stocks poised for outperformance. Recommendations from previous editions of this report have produced gains of +205%, +258% and +477%. The stocks in this report could perform even better.See these 7 breakthrough stocks now>>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 GlaxoSmithKline plc (GSK): Free Stock Analysis Report Omnicell, Inc. (OMCL): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research