The National Hospital Insurance Fund (NHIF) is now demanding proof of marriage before accepting applications to include spouses in the cover.
The new measure, aimed at checking rampant fraud, spells doom for thousands of couples who have been living together as husband and wife but without marriage certificates.
And it appears to have caught many NHIF contributors, seeking to include their spouses in the cover, by surprise.
One of them is Kisumu resident Collins Omondi, who visited the NHIF offices in the lakeside town on Wednesday, seeking to include his spouse as a beneficiary, only to be asked to produce a marriage certificate.
Mr Omondi said all he had carried was his wife's National Identity (ID) card and two passport-size photographs.
The directive indicates that for one's spouse to be included in the scheme, copies of the contributor's identification card, the spouse's ID, marriage certificate or an affidavit from a magistrates' court must be produced.
The NHIF strictly demands that an affidavit showing proof of marriage should not be from a lawyer but from a magistrate's court.
"I knew all I needed to produce was an ID card and her passport-size photos. I don't have a marriage certificate and getting an affidavit from a magistrate's court is another process altogether," Mr Omondi said.
Mr Willys Owino, who spoke to the Nation, said they have decided as a couple to have two separate cards.
"The process of getting my wife included in the cover is becoming impossible so the only alternative is for her to get her own card. I can add my children in the cover because I have their birth certificates," Mr Owino said.
Ms Marryanne Waweru says she visited NHIF offices two months ago but was lucky because she had inquired earlier and knew the necessary documents to carry.
"I had mailed the customer care services asking about the documents I needed to add my children and my husband in the cover. So I was told to carry my marriage certificate or an affidavit from a magistrate," she said.
The NHIF says the requirement was not entirely new as applicants have always been asked to produce such documents.
But it has now been made mandatory after it was discovered that some contributors included their girlfriends and mistresses as beneficiaries.
Chief Executive Officer Geoffrey Mwangi clarified that the documents are not needed during registration but only when one wants to make a change.
"This is just a measure to prevent possible fraud. We have had several cases of people presenting their relatives, especially those having medical problems, as their spouses," Mr Mwangi said.
The demand for a marriage certificate or affidavit will ensure no one presents the wrong person as a spouse, he said.
"Kenyans are very clever people. They come up with ways of survival every day. We have to put in place tough measures to curb such situations," he said.
The fund recently saved Sh1.9 billion after a crack down on hospitals making fake claims.
It paid Sh11.6 billion for the six months to December, from Sh13.5 billion in the first half of 2017.
The claims were mainly from overrated procedures.
For instance, hospitals would bill the fund for three dialysis sessions yet it performed only one or charge for Caesarean-section births for normal deliveries.
There were also cases of impersonation and hospitals launching claims with the intention to defraud NHIF using members' cards without their consent.
Mr Mwangi reckons the introduction of the "second tier scrutiny of claims" has substantially cut fraudulent claims.