Our Weekly Checkup takes the temperature of the medical device industry’s three largest U.S. clusters: Massachusetts, California and Minnesota.

The MassDevice Indices are weighted according to market capitalization, based on the number of shares outstanding for each company and each Friday’s closing share price.

The Massachusetts index for the week ended August 26 closed at 5.48, up 5.4 percent compared with the prior week. Since Jan. 1, 2009, when we began tracking these companies, the index has risen 23.7 percent.

The Minnesota index for the week ended August 26 closed at 4.60, up 8.1 percent compared with the prior week. Since Jan. 1, 2009, when we began tracking these companies, the index has risen 55.8 percent.

The California index for the week ended August 26 closed at 10.89, up 8.2 percent compared with the prior week. Since Jan. 1, 2009, when we began tracking these companies, the index has risen 156.6 percent.

We also create a composite index of the three regional indices and compare it with four other indices (the S&P 500, the Dow Jones Industrial Average, the Dow’s IHI medical devices index and the NASDAQ exchange):

The Weekly Checkup also compares Monday morning’s opening share prices with their value when the markets close Friday afternoon to calculate the biggest gainers and losers.

Here are the 20 firms that posted the biggest share price gains and losses during the week ended August 26:

The 10 biggest gainers:

1. Thermage Inc. (Solta Medical Inc.): 25% (open $1.4; close $1.75)
2. Hansen Medical Inc. : 11.58% (open $2.85; close $3.18)
3. Biolase Technology Inc. : 11.03% (open $2.9; close $3.22)
4. SeraCare Life Sciences: 8.96% (open $3.35; close $3.65)
5. Alphatec Holdings Inc. : 8.44% (open $2.25; close $2.44)
6. Staar Surgical Company : 8.27% (open $7.62; close $8.25)
7. Imaging3 Inc. : 7.59% (open $0.079; close $0.085)
8. Biomerica Inc. : 7.14% (open $0.42; close $0.45)
9. Digirad Corp. : 6.75% (open $2.37; close $2.53)
10. Cambridge Heart Inc.: 6.67% (open $0.15; close $0.16)

Sources: Google Finance and Yahoo! Finance.

And the 10 biggest losers:

1. Acusphere Inc.: -8.82% (open $0.085; close $0.0775)
2. NeuroMetrix Inc.: -5.78% (open $0.3736; close $0.352)
3. Interleukin Genetics Inc.: -5.41% (open $0.37; close $0.35)
4. Enteromedics Inc. : -2.85% (open $2.46; close $2.39)
5. Rochester Medical Corp. : -0.36% (open $8.45; close $8.42)
6. OPTOS: -0.31% (open $159.75; close $159.25)
7. Intraop Medical Corp. : 0% (open $0.15; close $0.15)
8. Integrated Surgical Systems Inc. : 0% (open $0.335; close $0.335)
9. Trimedyne Inc. : 0% (open $0.106; close $0.106)
10. World Heart Inc. : 0% (open $0.4; close $0.4)

Sources: Google Finance and Yahoo! Finance.

Disclaimer: MassDevice.com’s rankings do not reflect an opinion of companies’ health, prospects or viability. They are intended to provide a snapshot of publicly traded medical device companies and in no way constitute a recommendation to buy or sell any particular security, portfolio of securities, transaction or investment strategy.