Women and health workers have been warned a brand of pregnancy test has been returning false results - indicating no pregnancy, when in fact the woman is carrying a baby.
The Health Ministry's Medsafe division says it has received "several" reports from health workers, district health boards and clinics about the EasyCheck Pregnancy Test Cassette. The problems relate to "false negative test results and technical faults".
The supplier, Phoenix MedCare, says it has heard of only two unconfirmed cases.
Medsafe's response has been to monitor reports about the device and to place an early warning system note on its website asking consumers and health workers to notify it of problems with the product. However, the Auckland Women's Health Council labelled the response "pathetic" and is demanding a recall.
"They should get it taken off the market," said council co-ordinator Lynda Williams.
Medsafe is not ruling out a recall if it is warranted after further investigation.
Ms Williams said a false negative result could lead to a pregnant woman believing she was not pregnant, so she might continue drinking alcohol, which could harm the fetus. Or she might not want to have a baby and a false negative result could unnecessarily delay having an abortion.
"A false negative is very confusing for women when they [suspect] they are pregnant. It causes some disconnection between their knowledge of what's going on in their bodies and what this false pregnancy reading gives them when they are pregnant."
The EasyCheck Test Cassette, which measures a pregnancy-related hormone level in urine, is state-funded through Pharmac for use by doctors, midwives and other health workers. Phoenix MedCare said the Chinese-made product was not available for purchase by the public at pharmacies.
Medsafe says the cassette test is intended to be used as a first-line pregnancy check from 10 days after conception and followed up with a blood test to confirm pregnancy if there is any doubt.
Family Planning staff make frequent use of the cassette test, which is the only Pharmac-funded urine test for pregnancy, said the group's national medical adviser Dr Christine Roke. She was aware of a handful of cases in which the cassette test had not worked properly, including some false negatives.
"Mostly it's that they have been inconclusive so we've [retested]."
Phoenix managing director Brad Rodger said there was "one alleged report of a false negative" in December and one unconfirmed report of another in January. The company, which began supplying the cassette test kits last July, had supplied more than 500,000 since then.
"During this period there has been some minor feedback with tests showing incomplete control lines from isolated sites in a minor number. This is likely due to incorrect procedural or storage techniques. We have not been able to replicate this issue unless we purposely follow an incorrect testing method.
"In the 12 months to December 2015 there were [around] 2.94 million of this test type supplied worldwide, with no reportable adverse events.
"We do not know the cause of the two alleged false negatives. We were not supplied with this information when it was requested."
Medsafe compliance manager Derek Fitzgerald said: "When investigating claims of problems with medical devices, [options] may include fault with the product, user error or the need for user education. Recall of the product ... could be considered after further investigation."
• A false negative pregnancy test result could lead to:
• A woman continuing to drink alcohol, potentially harming the baby.
• An unnecessary delay in having an abortion, if the woman did not want to have a baby.
• Confusion for a woman who suspects she is carrying a baby but a false test result tells her she is not pregnant.
Source: Women's health campaigner Lynda Williams