Sen. Ronald “Bato” Dela Rosa, chairperson of the Committee on Public Order and Dangerous Drugs, presides over the public inquiry on the allegedly inhumane and irregular acts done by police officers and unknown individuals against Mayor Samson Dumanjug of Bonifacio, Misamis Occidental. Joseph B. Vidal, Senate PRIB/File

MANILA — Can a hair follicle test be done on a bald person to determine potential drug use?

This was the question of Sen. Ronald "Bato" dela Rosa to the Philippine Drug Enforcement Agency (PDEA) during the hearing on the agency’s proposed 2025 budget of P3.8 billion.

PDEA Director General Moro Virgilio Lazo said hair from other parts of the body can be used.

"Puwede yung hair sa ilong, hair sa genitals?" Dela Rosa asked.

(Can you use nose hair or hair on the genitals?)

“Puwede lahat (You can use anything),” Lazo said.

READ: Sara Duterte backs drug test on gov't officials: 'Para siguradong nasa tamang pag-iisip'

PDEA said, however, that they are not yet capable of doing a hair follicle drug test and is still developing the process for it. 

Asked how far back this type of test can detect drug use, PDEA Laboratory Service Acting Director Angela Salvador said, "The standard period for detection of drugs in hair, it would vary, but the average is 90 days.”

Urine tests can detect methamphetamine or shabu use from two to five days.

Hair follicle tests were in the news in recent months after President Ferdinand Marcos Jr's critics — including former President Rodrigo Duterte — demanded that he take one to address alleged drug use.

Rumors of Marcos' drug use also circulated in the run-up to the 2022 elections, when he submitted negative drug tests to PDEA and the National Bureau of Investigation.

Not just for high officials: Duterte bill makes hair follicle tests the standard for screening

The rumors were revived by the screening by Duterte supporters abroad of a video of a man they alleged was Marcos appearing to do drugs. Authorities, including the NBI and the Department of Information and Communications Technology, have dismissed the video as fake. 

RELATED VIDEO: