The Thai athlete returned an Adverse Analytical Finding (AAF) for two Prohibited Substances in an In-Competition urine sample collected on 3 August 2022 at the 11th ASEAN Para Games 2022 in Solo, Indonesia. The test was conducted by the Asian Paralympic Committee (APC) in its role as the Major Event Organisation for the 11th ASEAN Para Games. The substances tested were chlorothiazide and hydrochlorothiazide. The substances are included in the World Anti-Doping Agency (WADA) Prohibited List for 2022 under class S5 (diuretics and masking agents). Both are Specified Substances under the Code. The APC had initial results management authority in the athlete's case under the APC's anti-doping rules with respect to determining whether the athlete had committed an ADRV and the disqualification of any results from the 11th ASEAN Para Games. Marnnok was provisionally suspended by the APC on 29 September 2022 pending a resolution of his case. 

On 31 March 2023, the APC issued a reasoned decision confirming that the athlete had committed an ADRV and disqualifying his results from the 11th ASEAN Para Games, together with all resulting consequences, including forfeiture of all related medals, points and prizes. The matter was then referred to the IPC, as the International Federation for the athlete's sport (Para Swimming) - to determine any further applicable consequences for the athlete, including any period of ineligibility under the terms of the Code. 

The swimmer has accepted the consequences proposed by the IPC in resolving his case. As a result of his violation, he will be ineligible for competition and other sports activities (other than approved anti-doping education or rehabilitation programmes) from 29 September 2022 until 28 September 2024. All results obtained by the athlete from the date of the sample collection (3 August 2022) until the start of the provisional auspension (29 September 2022) will be disqualified, with all resulting consequences, including forfeiture of any medals, points and prizes. 

Each athlete is fully responsible for the substances found in his/her sample. An ADRV occurs whenever a prohibited substance (or its metabolites or markers) is found in the athlete's sample, whether or not the athlete intentionally or unintentionally used a Prohibited Substance or was negligent or otherwise at fault. As a signatory to the World Anti-Doping Code (the WADC), the IPC remains committed to a doping-free sport environment at all levels. The IPC has established the IPC Anti-Doping Code in accordance with the general principles of the WADC, including the WADC International Standards, and expects to lead the fight against doping in sport for impaired athletes in the spirit of sport. 

The IPC is the international governing body for five Para sports: World Para Athletics, World Para Ice Hockey, World Para Powerlifting, World Shooting and World Para Swimming. The IPC's vision is to create an inclusive world through Para sports.