The only authorized anti-doping laboratory in southeast Asia has been forced to suspend operations, leaving a gap in coverage for much of the region.
The World Anti-Doping Agency has ruled the National Doping Control Centre in Thailand can't test samples for up to six months because of non-conformities found during inspections.
WADA's statement late Wednesday didn't specify the lab's exact shortcomings.
Relevant samples must be securely transported to another WADA-accredited laboratory for analysis, WADA said.
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.
That leaves the nearest authorized lab in Beijing, nearly 3,300 kilometers (2,050 miles) away.
A WADA crackdown on substandard testing led to the suspension of the lab in India in August and the complete shutdown of a facility in Kazakhstan in 2017.
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That leaves Asia with only five laboratories and large distances between them. They are in Turkey and Qatar in the west, and Japan, China and South Korea in the east.
Shipping substances long distances generally means higher costs for national anti-doping agencies. Many southeast Asian countries' agencies already struggle for funding and conduct a fraction of the tests done by European countries.
The Bangkok lab tested 3,429 samples in 2017, the last year for which statistics are available, ranking it among the world's smaller facilities.