Single Step, Direct ELISA Measures Free Testosterone

A single-step direct ELISA measurement of free testosterone saves laboratories time and money while reducing the possibility of errors.

The ability to directly measure free testosterone eliminates the complication of taking multiple indirect measurements and calculating free testosterone through an algorithm. Diagnostic technologies have inherent limitations in terms of both precision and accuracy. Combining multiple procedures worsens these limitations and increases both the cost and opportunity for errors.


The ThunderBolt delivers power and flexibility in a small size. The dual function analyzer provides complete, walk-away automation of 192 patient samples in only a 61 cm by 61 cm space. Completely open architecture allows any enzyme immunoassay (EIA) or clinical laboratory improvement amendments (CLIA) protocol to be programmed. Up to eight different protocols can run in a single batch. Intuitive and robust software further enriches the ThunderBolt, making it the total laboratory automation solution. The ThunderBolt delivers power and flexibility in a small size.

The combination of free and total testosterone gives healthcare professionals more information to make the correct diagnosis when a testosterone-related condition is suspected. Gold Standard Diagnostics (GSD; Davis, CA, USA) also offers an ELISA test for total testosterone level to complement the free testosterone assay.

Total testosterone measures levels of all forms in the blood stream, including: unbound (free), loosely bound to albumin and tightly bound to sex-hormone binding globulin (SHBG). Many common factors influence SHBG levels. As a result, a total testosterone assessment may yield a normal result, but due to higher or lower levels of testosterone-SHBG bonding, the concentration of free testosterone may not correlate directly with total testosterone readings.

SHBG levels can be increased by factors such as obesity and testosterone treatment. Factors that can decrease SHBG levels include aging, pregnancy, and estrogen therapy. Symptoms of low testosterone in males include decreased sexual function, erectile dysfunction, loss of hair, decreased muscle mass, and osteoporosis. For females, symptoms include hot flashes, irritability, decreased libido, and insomnia.

Gold Standard Diagnostics (GSD) provides comprehensive diagnostic solutions that improve lab efficiency and minimize overall costs. Through an extensive product menu, automated instrument platforms, and good customer service, GSD solves laboratory problems.

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