Stock Quotes in this Article: IDXX, VAR, ACHC, OMED

DELAFIELD, Wis. (Stockpickr) -- Professional traders running mutual funds and hedge funds don't just look at a stock's price moves; they also track big changes in volume activity. Often when above-average volume moves into an equity, it precedes a large spike in volatility.

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Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors."

Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it's always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock.

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With that in mind, let's take a look at several stocks rising on unusual volume today.

Varian Medical Systems

Varian Medical Systems (VAR) is a manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, proton therapy and brachytherapy. This stock closed up 1.5% at $79.24 in Monday's trading session.

Monday's Volume: 1.53 million

Three-Month Average Volume: 773,698

Volume % Change: 97%

From a technical perspective, VAR jumped modestly higher here with above-average volume. This stock has been uptrending strong for the last month, with shares moving higher from its low of $71.98 to its intraday high of $79.34. During that move, shares of VAR have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of VAR within range of triggering a big breakout trade. That trade will hit if VAR manages to take out Monday's high of $79.34 to its 52-week high at $80.66 with high volume.

Traders should now look for long-biased trades in VAR as long as it's trending above some near-term support levels at $77 or at $76 and then once it sustains a move or close above those breakout levels with volume that's near or above 773,698 shares. If that breakout hits soon, then VAR will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $85 to $90.

OncoMed Pharmaceuticals

OncoMed Pharmaceuticals (OMED) is engaged in the development of monoclonal antibody drugs that target cancer stem cells. This stock closed up 4% at $14 in Monday's trading session.

Monday's Volume: 184,000

Three-Month Average Volume: 119,606

Volume % Change: 85%

From a technical perspective, OMED spiked sharply higher here with above-average volume. This stock has been downtrending badly for the last four months, with shares moving lower over $30 to its recent low of $12.06. During that downtrend, shares of OMED have been consistently making lower highs and lower lows, which is bearish technical price action. That said, shares of OMED have started to reverse its downtrend and enter a short-term uptrend, with shares moving higher from $12.06 to its intraday high of $14.15. That move has now pushed shares of OMED within range of triggering a near-term breakout trade. That trade will hit if OMED manages to take out its 50-day moving average of $14.32 with high volume.

Traders should now look for long-biased trades in OMED as long as it's trending above Monday's low of $13.25 or above $13 and then once it sustains a move or close above $14.32 with volume that's near or above 119,606 shares. If that breakout hits soon, then OMED will set up to re-test or possibly take out its next major overhead resistance levels at $16 to $17.93. Any high-volume move above $17.93 will then put $19.50 to $20 into range for shares of OMED.

Idexx Laboratories

Idexx Laboratories (IDXX) develops, manufactures and distributes products and provides services for the veterinary, bioresearch, livestock and poultry, water and dairy markets. This stock closed up 0.83% at $105.02 in Monday's trading session.

Monday's Volume: 733,000

Three-Month Average Volume: 292,631

Volume % Change: 124%

From a technical perspective, IDXX bounced modestly higher here back above its 50-day moving average of $104.79 with above-average volume. This stock has been downtrending for the last month, with shares moving lower from its high of $113.11 to its intraday low of $103.11.

During that move, shares of IDXX have been making mostly lower highs and lower lows, which is bearish technical price action. That said, shares of IDXX could now be ready to reverse its downtrend and possibly bounce higher.

Traders should now look for long-biased trades in IDXX as long as it's trending above Monday's low of $103.11 and then once it sustains a move or close above Monday's high of $105.48 with volume that's near or above 292,631 shares. If we get that move soon, then IDXX will set up to re-test or possibly take out its next major overhead resistance levels at $108.82 to $110. Any high-volume move above those levels will then give IDXX a chance to challenge its 52-week high at $113.11.

Acadia Healthcare

Acadia Healthcare (ACHC) develops and operates a network of behavioral health facilities. This stock closed up 4.8% at $48.46 in Monday's trading session.

Monday's Volume: 605,000

Three-Month Average Volume: 228,175

Volume % Change: 145%

From a technical perspective, ACHC spiked sharply higher here right off some near-term support at $46 and into new 52-week-high territory with above-average volume. This stock has been uptrending strong for the last six months, with shares soaring higher from its low of $30.70 to its intraday high of $49.14. During that uptrend, shares of ACHC have been consistently making higher lows and higher highs, which is bullish technical price action.

Traders should now look for long-biased trades in ACHC as long as it's trending above some key near-term support levels at $46 or at $43 and then once it sustains a move or close above its new 52-week high at $49.14 with volume that's near or above 228,175 shares. If we get that move soon, then ACHC will set up to enter new 52-week high territory, which is bullish technical price action. Some possible upside targets off that move are $55 to $60.

To see more stocks rising on unusual volume, check out the Stocks Rising on Unusual Volume portfolio on Stockpickr.

-- Written by Roberto Pedone in Delafield, Wis.


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At the time of publication, author had no positions in stocks mentioned.

Roberto Pedone, based out of Delafield, Wis., is an independent trader who focuses on technical analysis for small- and large-cap stocks, options, futures, commodities and currencies. Roberto studied international business at the Milwaukee School of Engineering, and he spent a year overseas studying business in Lubeck, Germany. His work has appeared on financial outlets including

CNBC.com and Forbes.com. You can follow Pedone on Twitter at www.twitter.com/zerosum24 or @zerosum24.