Secondary immunodeficiency assessment (Assessment of secondary (acquired) immunodeficiency)
A specialist assessment to find out whether another illness or its treatment is weakening the immune system, how badly, and what can be done to protect against infection.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- Secondary immunodeficiency means the immune system is weakened by another illness or its treatment, such as blood cancers, certain medicines (for example rituximab), or protein loss.
- Assessment combines antibody levels with vaccine-response testing and a careful review of the underlying cause — low antibody levels alone do not tell the whole story.
- It is more common than inherited immunodeficiency, and the picture can change as the underlying condition or treatment changes.
- Where the weakness is significant and infections are a problem, treatments such as vaccines, preventive antibiotics or immunoglobulin replacement can greatly reduce illness.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
A clear picture of whether, and how much, your immune system is weakened
An acute, severe infection needs urgent medical care now, not a routine assessment.
You usually have blood tests taken and may be given a vaccine for response testing. You leave with an explanation of the findings so far and a plan.
A prevention plan agreed jointly with the team treating your underlying condition.
You usually have blood tests taken and may be given a vaccine for response testing. You leave with an explanation...
Antibody levels and other routine results come back and the picture starts to take shape.
If vaccine-response testing was started, you return for a blood test to see how well your antibodies responded.
A prevention and treatment plan is agreed with the team treating your underlying condition; immunoglobulin...
What is a secondary immunodeficiency assessment?
Secondary (or acquired) immunodeficiency means the immune system has been weakened by something else, rather than being born that way. Common causes include blood cancers such as chronic lymphocytic leukaemia (CLL) and myeloma, some medicines — particularly drugs like rituximab that reduce the cells which make antibodies — long-term steroids and other immune-suppressing treatments, and conditions where the body loses protein. It is much more common than primary (inherited) immunodeficiency.
An assessment is an appointment with a consultant immunologist, often working alongside the team treating the underlying condition, to work out whether the immune system is genuinely affected, how badly, and what to do about it. The aim is to protect the person from infection without over-treating.
The assessment usually includes a detailed history, an examination, and blood tests — measuring antibody (immunoglobulin) levels and how well the body responds to vaccines. Just as important is reviewing the underlying illness and the medicines that may be responsible.
It is worth understanding what the assessment can and cannot do. It can identify a treatable weakness, guide vaccines and preventive antibiotics, and decide whether immunoglobulin replacement is justified. It cannot cure the underlying cause, and the immune picture can change as the underlying condition or its treatment changes.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Primary versus secondary immunodeficiency
| Primary (inherited) | Secondary (acquired) | |
|---|---|---|
| Underlying cause | Born with it | Another illness or its treatment |
| How common | Individually uncommon | More common |
| Often linked to | Genetic conditions | Blood cancers, certain drugs, protein loss |
| Can the cause change | Usually lifelong | May improve if the cause is treated or stopped |
Both are assessed with similar immune tests, but secondary immunodeficiency always involves looking hard at the underlying cause.
Preparing for your test
- Bring details of any underlying condition, especially blood disorders or cancers, and the team treating them.
- List all your medicines, highlighting recent or current treatments such as rituximab, chemotherapy, steroids or other immune-suppressing drugs.
- Make a timeline of your infections: how often, how severe, where, and how they were treated.
- Note hospital admissions or infections that needed intravenous (drip) antibiotics.
- Bring records of previous blood tests, including any antibody levels, and your vaccination history.
- Note other symptoms such as tiredness, weight loss, swollen glands or recurrent chest infections.
- Be ready for vaccine-response testing, which may mean a vaccine and a return visit about four weeks later.
What happens
The consultant immunologist reviews your underlying condition and medicines, takes a history of your infections, and examines you. A key part of the assessment is deciding how much of the immune weakness is due to the disease itself and how much to its treatment.
You usually have blood tests measuring immunoglobulin (antibody) levels, sometimes with protein electrophoresis. To judge how well your remaining antibodies work, you may be given vaccines — such as pneumococcal vaccine — and asked to return about four weeks later for a blood test.
The immunologist often works with the team treating your underlying condition to agree a plan. You leave with an explanation of the findings so far, which tests have been requested, and a plan for prevention and follow-up. Where infections are frequent or severe and the immune weakness is significant, treatments such as preventive antibiotics or immunoglobulin replacement may be considered.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- An acute, severe infection needs urgent medical care now, not a routine assessment.
- A single antibody level in isolation does not capture how well the immune system is working.
- Unproven 'immune boosting' tests and supplements have no role in assessing secondary immunodeficiency.
- If the underlying cause is not yet diagnosed, that diagnosis usually needs to come first or run alongside.
Delay or rearrange if…
- You are acutely unwell or septic — seek emergency care instead.
- You have very recently had rituximab, chemotherapy or other treatment that will skew the results — timing matters.
- You have recently had a vaccine or infection, which can affect immune tests.
- You cannot yet gather the details of your underlying condition, medicines and previous results.
Alternatives to discuss
- Optimising treatment of the underlying condition, which may improve immunity.
- Vaccination and preventive antibiotics without immunoglobulin replacement where that is enough.
- Watchful waiting with a clear plan for new infections where the weakness is mild.
- Reviewing whether a causative medicine can be changed, with the prescribing team.
- A second opinion at a specialist immunology centre for complex cases.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- A clear picture of whether, and how much, your immune system is weakened
- Identification of a medicine or condition that may be responsible
- A tailored plan to prevent infections, including the right vaccines
- A reasoned decision on whether immunoglobulin replacement is justified
- Coordinated care with the team treating your underlying condition
- Fewer infections and hospital admissions where treatment is needed and effective
Risks & complications
- Discomfort or bruising from blood tests
- Needing a vaccine and a return visit for vaccine-response testing
- A picture that changes as the underlying condition or its treatment changes
- Results that need careful interpretation alongside the underlying illness
- Uncertainty about how much of the weakness is due to the disease versus its treatment
- Anxiety while waiting for results or while infections continue
- Needing to balance immune protection against treatment for the underlying condition
- A finding that prompts a change to cancer or immune-suppressing treatment, decided with the treating team
- A serious infection occurring during the assessment, which needs urgent care
The main challenge is judging how much the immune weakness matters and whether it will improve when the underlying cause is treated. Decisions — especially about immunoglobulin replacement, which is a human blood product in limited supply — should be made with the team treating your underlying condition and against clear criteria. Make sure you understand which tests are being done, what each result would change, and how prevention will be handled. Tell the immunologist about every medicine, particularly recent rituximab or chemotherapy.
Published figures to discuss
Secondary immunodeficiency varies hugely with its cause, so single 'success' or 'accuracy' figures are not meaningful. Results are interpreted alongside the underlying illness and medicines, and the picture changes over time. The notes below are broad and for context only.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Low antibody levels after rituximab | Common during and for months after treatment | B-cell-depleting drugs reduce antibody production; levels often recover over many months but not always, so monitoring matters. | Guide sourcesClinical context |
| Secondary immunodeficiency in blood cancers such as CLL and myeloma | Reported in a large proportion of patients | It is common in these conditions, but only some people need immunoglobulin replacement; careful selection against criteria is essential. | Guide sourcesClinical context |
| Reduction in infections after immunological assessment and treatment | Studies report fewer hospital admissions for infection | Benefit is seen with immunoglobulin replacement and with preventive antibiotics in selected patients; results vary by person. | The expanding field of secondary antibody deficiency: causes, diagnosis and management — PMCpmc.ncbi.nlm.nih.govSource-linked context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery from the assessment. 'Afterwards' is about completing the tests — including any return visit for vaccine-response testing — waiting for results, and following a prevention plan agreed with the team treating your underlying condition.
- Waiting days to weeks for antibody results
- A return visit for vaccine-response testing about four weeks after a vaccine
- A plan that is agreed jointly with another specialist team
- A picture that changes over time as treatment for the underlying condition changes
- Starting preventive measures before any decision about immunoglobulin replacement
Aftercare
- Complete all requested blood tests, including the return visit for vaccine-response testing.
- Follow the agreed prevention plan, such as vaccines or preventive antibiotics.
- Keep a record of any infections and treatments to bring to follow-up.
- Seek medical help promptly for new infections, as advised for your situation.
- Tell other clinicians about your immune assessment, especially before vaccines or further immune-suppressing treatment.
- Make sure the immunology and treating teams stay in touch about your care.
- Attend follow-up so results and the plan can be reviewed as your underlying condition changes.
- Details of underlying condition and treating team provided
- Full medicine list, including recent rituximab or chemotherapy, shared
- Antibody blood tests completed
- Return visit for vaccine-response testing booked
- Prevention plan (vaccines, antibiotics) understood
- Plan for seeking help with new infections clear
- Joint follow-up with the treating team arranged
⚠ Get urgent help if…
- A high fever with feeling very unwell, especially while on immune-suppressing treatment
- A severe or rapidly spreading infection, or one not responding to treatment
- Breathlessness, chest pain or coughing up blood
- Signs of sepsis: confusion, very fast breathing, mottled or pale skin — call 999
- Persistent fevers, drenching night sweats or unexplained weight loss
- Repeated infections needing intravenous antibiotics or hospital admission
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good outcome is a clear understanding of whether your immune system is meaningfully weakened, by what, and a plan that protects you from infection while your underlying condition is managed. Sometimes the result is reassurance that, despite treatment, your immune protection is adequate and only simple prevention is needed.
The assessment cannot cure the underlying cause, and the immune picture can change — for example, antibody levels may recover after a course of rituximab, or fall further with more treatment. Results are interpreted alongside your illness and medicines, and the plan is reviewed over time. A decision not to start immunoglobulin replacement is not a failure; it often means simpler measures are enough or that the criteria are not yet met.
How long a secondary immunodeficiency lasts depends on its cause. Some improve when a medicine is stopped or the underlying condition is treated — for example, antibody levels may recover over months after rituximab. Others persist while the underlying illness or its treatment continues. Because of this, the assessment is rarely a one-off: it is repeated or reviewed as the underlying situation changes.
Related tests, treatments or support
A secondary immunodeficiency assessment is almost always combined with care from the team treating the underlying condition — most often haematology for blood cancers, but also rheumatology, nephrology, neurology or transplant teams depending on the cause. It may also be combined with respiratory review where there are recurrent chest infections or lung damage.
Follow-up & long-term care
Follow-up is arranged jointly with the team treating your underlying condition, to review results and adjust prevention as your situation changes. Antibody results come back within days to weeks and vaccine-response testing takes about four weeks. Ask who to contact if you develop a significant infection while your assessment is ongoing.
- Keep vaccinations up to date as advised, around the timing of any immune-suppressing treatment
- Continue any preventive antibiotics or immunoglobulin replacement as planned
- Have antibody levels rechecked as advised, especially after treatments such as rituximab
- Report changes in your pattern of infections promptly
- Keep the immunology and treating teams informed of changes to your underlying condition or its treatment
Repeat, follow-on and what comes next
- The picture is reassessed as the underlying condition or its treatment changes.
- Antibody levels may recover (for example after rituximab) and treatment can then be reduced or stopped.
- A decision to start, continue or stop immunoglobulin replacement is reviewed against clear criteria.
- Some people need only prevention, while others move to long-term replacement as the picture evolves.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A prevention plan agreed jointly with the team treating your underlying condition.
- A named contact and route for results and for new infections.
- Scheduled rechecking of antibody levels, especially after treatments such as rituximab.
- Clear criteria and regular review for any immunoglobulin replacement.
- Up-to-date, individualised vaccination advice timed around immune-suppressing treatment.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Length and complexity of the consultation
- Review of the underlying condition and its treatment
- Blood tests including immunoglobulin levels and protein electrophoresis
- Vaccine-response testing, which needs a vaccine and a repeat blood test
- Repeat testing as the underlying situation changes
- Follow-up appointments and coordination with the treating team
- The consultant's appointment fee
- Which tests are included and the cost of any specialised assays
- The cost of the vaccine and the return visit for vaccine-response testing
- Cost of repeat testing as your situation changes
- Cost of follow-up appointments and joint review with the treating team
- Whether onward referral or specialist treatment is included
- What happens, and what it costs, if the assessment is inconclusive, and the cancellation policy
On the NHS? Secondary immunodeficiency is assessed on the NHS when clinically indicated, usually alongside the team treating the underlying condition; private appointments may be used for speed or a second opinion.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Starting immunoglobulin replacement without trying vaccines and preventive antibiotics where appropriate.
- Not coordinating with the team treating the underlying condition.
- Failing to recheck antibody levels after a treatment such as rituximab, missing recovery or worsening.
- Not explaining that immunoglobulin is a human blood product used against clear criteria.
- No clear plan for who manages prevention and who to contact about new infections.
Marketing red flags
- Routine 'immune system checks' marketed as catching every problem.
- Supplements or infusions sold to 'boost immunity' alongside serious treatment.
- Starting immunoglobulin replacement without clear criteria or review.
- Not mentioning that the immune picture changes with the underlying condition.
- Downplaying the importance of treating the underlying cause.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- How much of my immune weakness is due to my illness, and how much to its treatment?
- Which tests are you requesting, and what would each result change?
- Will my immune system recover if a medicine is stopped or changed?
- What vaccines and preventive measures should I have, and when?
- Would immunoglobulin replacement be justified for me, and what are the criteria?
- How will you and my treating team coordinate my care and follow-up?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
What causes a secondary immunodeficiency?
Can a medicine really weaken my immune system?
Will my immune system recover?
Will I be given immunoglobulin replacement?
Can I be assessed on the NHS?
Why do I need vaccine-response testing?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: UK Primary Immunodeficiency Network (UKPIN) The expanding field of secondary antibody deficiency: causes, diagnosis and management — PMC Secondary immunodeficiency in haematological malignancies (CLL and myeloma) — PMC Clinical and laboratory characteristics of secondary immunodeficiency after treating haematological malignancies — PMC Clinical guidelines for immunoglobulin use (UK Department of Health) — GOV.UK NHS — Sepsis (urgent help with infection)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
Related guides: Clinical immunology consultation · Primary immunodeficiency diagnosis · Recurrent infection assessment · Immunoglobulin replacement therapy (IVIG) · Subcutaneous immunoglobulin therapy