The sample of a Nyeri patient who tested positive for coronavirus was not sent from the county.
Nyeri county says the person is likely to have jetted into the country and consequently quarantined.
County director of Medical Services Nelson Muriu on Friday said all the tests sent from the county tested negative.
"I want to confirm that the samples submitted by the Department of Health to the National Influenza Centre were all negative, and this includes the three that were submitted this week," Muriu said.
"My first hypothesis is that this could be one of those persons on self-quarantine but hails from Nyeri."
He said the self-quarantine form captures physical address.
"My second hypothesis is that someone could have presented themselves for testing in other approved private labs," Muriu added.
The government said it was a case whose identity card read Nyeri but from a quarantine centre after the person flew into the country.
"This is not a Nyeri case but only referring to the home county."
On Friday during a daily press briefing, Health CAS Mercy Mwangangi said 12 more people had tested positive, with one of them coming from Nyeri and another from the neighbouring Laikipia county.
This now brings the number of the total number of people who have tested positive in Kenya to 122 cases.
Edited by E.Kibii
