SANTA CLARA, Calif. (AP) ¿ Affymetrix Inc., which makes genetic analysis technology, on Wednesday reported a narrower third-quarter loss, but the results missed Wall Street expectations, sending shares plunging in after-hours trading.

The company posted a loss of $8.8 million, or 13 cents per share, in the three months ended Sept. 30. That compares with a year-ago loss of $31.8 million, or 46 cents per share, which included a hefty restructuring charge.

Revenue rose 4 percent to $78.2 million.

Analysts surveyed by Thomson Reuters expected a smaller loss of 8 cents per share on $80.7 million in sales, on average. Shares tumbled $1.36, or 15 percent, to $7.50 in aftermarket trading, having closed earlier up 20 cents at $8.86.

The company said product revenue and shipment revenue climbed during the quarter. It said it shipped 21 systems, bringing the total number of systems shipped to about 1,890.

The company also said its gross margin improved by 5 points, though the company hopes to further improve its margins with new products.

Shares have risen from a 52-week low of $1.79 in March to reach a high of $10.06 earlier this month.

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