The World Anti-Doping Agency (WADA) has suspended the accreditation of the Bangkok Laboratory, the only facility authorised by the global watchdog in Southeast Asia.
WADA took the decision because of non-conformities with international standards found during inspections of the laboratory in the Thai capital.
The National Doping Control Centre in Thailand is unable to carry out any anti-doping activities, including all analysis of urine and blood samples, during the period of suspension.
WADA said it would last up to six months, but the organisation can extend it if the issues uncovered are not rectified.
All samples will have to be transferred to a nearby WADA-accredited laboratory until the suspension is lifted, raising logistical concerns for the anti-doping process in the region.
"This is in order to ensure continued high-quality sample analysis, which also helps preserve athletes' confidence in this process and the wider anti-doping system," WADA said.
The accreditation of three other laboratories is currently suspended.
Facilities in New Delhi, Athens and Helsinki also cannot conduct anti-doping activities.
The Helsinki Laboratory is self-suspended "while it finalises its plan to relocate to a new facility, under a new host organisation".