Stabilization of human urine doping control samples: IV. Human chorionic gonadotropin

Area of Science:

• Biochemistry
• Analytical Chemistry
• Sports Science

Background:

• Proteolytic enzymes in urine can degrade human chorionic gonadotropin (hCG).
• Elevated temperatures during sample transport can also damage the hCG molecule.
• Maintaining sample integrity is crucial for accurate anti-doping analysis.

Purpose of the Study:

• To apply a stabilization mixture to athletes' urine samples.
• To chemically inactivate proteolytic enzymes and prevent hCG degradation.
• To assess the mixture's efficacy against temperature and proteolytic manipulation.

Main Methods:

• Urine samples were spiked with proteases or E. coli.
• Samples were incubated with or without a stabilization mixture (antibiotics, antimycotics, protease inhibitors).
• Intact hCG levels were measured using the EIAgen Total hCG kit.

Main Results:

• Incubation at 37°C reduced hCG levels in untreated samples.
• The stabilization mixture prevented hCG degradation by four of the six tested proteases.
• No significant difference in hCG levels was observed with E. coli inoculation between treated and untreated samples.

Conclusions:

• The chemical stabilization mixture enhances the quality of athletes' urine samples.
• It protects against deterioration from high temperatures and proteolytic manipulation.
• This approach improves the reliability of hCG testing in sports doping control.