On a trading day that saw the S&P 500 gain 0.4%, the Health Care sector (XLV) showed little change.

While being down today, the ETF, as a proxy for sector performance, tracked closer to the overall market today than over the past month. Entering today's trading, XLV was up 1.4% over the last thirty trading days while the S&P 500 was down 1.7%.

Novartis (NVS) declined 1.5% to close at $54.81, moving below its 50-day moving average of $55.17 and 200-day moving average of $55.67.

Volcano Corporation (VOLC) rose 2.5% to close at $26.28, approaching its 50-day moving average of $27.60. It has also moved closer to its 200-day moving average of $26.62. Abaxis (CNC) fell 1.2% to close at $28.62, moving closer to its 50-day moving average of $27.90. Also, the stock moved closer to its 200-day moving average of $41.42.

Align Technology (ALGN) was a major gainer in the sector, rising 15.7% (+$4.32) to close at $31.76 with five million shares moving. The stock traded in a range of $31.01 to $34.29. Share price is up $4.96 (18.5%) from $26.80 on March 23, 2012. Affymax (AFFY) was another big mover, climbing $1.36 (+11.7%) to a closing price of $12.95.

Dehaier Medical Systems (DHRM) was a major loser in the sector, falling 14.4% (-44 cents) to close at $2.62 with 90,747 shares moving. The stock traded between $2.62 and $2.97.