Understanding NK cell testing
What is NK cell testing?
Natural Killer (NK) cells are a type of immune cell found in the blood and the lining of the womb (endometrium). Their possible role in embryo implantation and recurrent miscarriage remains an area of ongoing research, and the evidence base continues to evolve.
Most failed fertility treatments and miscarriages are caused by chromosomal abnormalities within the embryo, rather than immune-related factors. However, in selected patients, particularly those with recurrent miscarriage, recurrent implantation failure, or autoimmune conditions, NK cell testing may be considered as part of a detailed fertility assessment.
Is NK cell testing evidence-based?
Understanding the current evidence
Current evidence in this area is limited and sometimes conflicting. Professional organisations including the Human Fertilisation and Embryology Authority (HFEA), the Royal College of Obstetricians and Gynaecologists (RCOG), and the American Society for Reproductive Medicine (ASRM) do not currently recommend routine immune testing or immune therapy in fertility treatment, as there is insufficient evidence that these interventions improve live birth rates.
For this reason, immune testing at Consilium Clinic is offered selectively and only when considered clinically appropriate, following specialist consultation.Further information about fertility treatment add-ons can be found on the HFEA Treatment Add-ons page. This includes information on treatments such as NK cell (NKC) testing and immune modulation therapy
Who it may help
When NK cell testing may be considered
NK cell testing may be considered in selected circumstances, including:
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recurrent miscarriage
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recurrent implantation failure
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a history of autoimmune conditions
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where no other clear explanation has been identified despite detailed investigation
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Whether testing is appropriate depends entirely on your medical history, fertility history, and individual circumstances. At your consultation, Ms Ben Nagi will carefully review your background and discuss whether NK cell testing is a relevant option for you.
Initial consultation
A detailed consultation to review your fertility history, previous investigations and treatment, and whether NK cell testing may be clinically appropriate for your circumstances.
NK cell assessment
Where considered appropriate, NK cells may be assessed in the blood and in the lining of the womb (endometrial biopsy). Your consultant will discuss which assessment is most relevant depending on your history.
Review of results
Your findings will be reviewed and discussed with you in detail, alongside the current evidence and what the results may or may not mean for your care.
Treatment planning (where appropriate)
Where immune-modulating treatment is considered, options may include Prednisolone (steroid tablets), Intralipid® infusion, or intravenous immunoglobulin (IVIG). These aim to alter immune activity, although there is currently no conclusive evidence that they improve pregnancy or live birth rates.
Ongoing review
Treatment recommendations are reviewed carefully throughout your care, with clear communication and the opportunity to ask questions at each stage.
Our approach
Care that feels consistent and personal
Immune testing and treatment represent a specialist and evolving area of fertility care. At Consilium Clinic, these are only offered where there is a clear clinical reason to consider them, and never as routine add-ons.
You will be given balanced, honest guidance about what testing can and cannot tell you, the current state of evidence, and what any treatment may or may not offer, so that you can make a fully informed decision about your care.
Wherever possible, Ms Ben Nagi remains directly involved throughout your care, providing continuity and the confidence of being supported by someone who understands your history and circumstances.
Consultant-led care
Your care, guided by experience
Your care is led by Ms Jara Ben Nagi, Consultant Gynaecologist and accredited specialist in Reproductive Medicine and Surgery.
With extensive experience in complex fertility care, including recurrent miscarriage and recurrent implantation failure, she provides thoughtful, evidence-based guidance tailored to your individual circumstances, helping you understand your options and make informed decisions about your care.
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Understanding risks and expectations
All immune tests and treatments at Consilium Clinic are considered optional fertility treatment add-ons and are not routinely recommended. Decisions regarding testing or treatment should be made following detailed discussion with your consultant, including careful consideration of the potential risks, costs, and uncertain benefits.
Where there is genuine clinical uncertainty, this will always be communicated clearly and honestly, so that any decision you make is fully informed.
Natural Killer (NK) cells are immune cells found in the blood and the lining of the womb. They are thought to play a possible role in implantation and early pregnancy, although their precise significance remains an area of active research.
No. NK cell testing is only offered in selected circumstances where there is a clinical reason to consider it, such as recurrent miscarriage, recurrent implantation failure, or a history of autoimmune conditions.
NK cells may be assessed in the blood and in the lining of the womb through an endometrial biopsy. Your consultant will discuss which assessment is most relevant to your history.
Immune-modulating treatments may include Prednisolone, Intralipid® infusion, or intravenous immunoglobulin (IVIG). These will only be recommended where considered clinically appropriate.