A BBC Sport investigation found there has not been any in-competition drug testing in the netball Superleague for five years.
Ukad's deputy director of operations Hamish Coffey said levels of testing in such leagues will "absolutely" increase as they grow.
"The hardest decision we make is less about where to test and more about where not to test," Coffey told BBC Sport. "It does come down to finite resource and us really trying to focus and prioritise testing resources where the greatest risk to clean sport is.
"Women's sport is developing and there is a greater public profile. We do reassess our testing resources on an ongoing basis."
Two top-flight men's competitions - the professional men's Elite Ice Hockey League and British Basketball League - also went untested by Ukad during the timeframe investigated.
The last time an in-competition test was conducted by Ukad for England Netball - which oversees the Superleague - was between 1 January and 31 March 2014.
While the data provided to BBC Sport, obtained via a Freedom of Information request, related specifically to Superleague, quarterly figures show 12 out-of-competition samples were collected for England Netball between 1 January and 31 March 2018.
It was during this time that the four home nations named their squads for the Commonwealth Games.
All Superleague netballers attend Ukad's '100% Me' course each year, and all team officials and coaches must complete other Ukad-led programmes.
England Netball says on its website that anti-doping rules are "consistent" with the World Anti-Doping (Wada) code and it works "in partnership with Ukad to prevent doping".
Read more from the BBC investigation here.
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By Kate Lightfoot