Part of
Infection & inflammation
Part of
Infection & inflammation
Blood biomarker
Part of
Infection & inflammation
Immunoglobulin A (IgA)
Immunoglobulin A (IgA)
Immunoglobulin A (IgA) is an antibody that protects mucous membranes in the gut and respiratory tract.
Immunoglobulin A (IgA) is an antibody that protects mucous membranes in the gut and respiratory tract.
Immunoglobulin A (IgA)
Normal range
Normal range
0.9-4.5 g/L
0.9-4.5 g/L
Normal range
0.9-4.5 g/L
0.9-4.5 g/L
Normal range
Immunoglobulin A (IgA)
Immunoglobulin A (IgA)
Immunoglobulin A (IgA) is an antibody that protects mucous membranes in the gut and respiratory tract.
Immunoglobulin A (IgA)
Normal range
0.9-4.5 g/L
Normal range
0.9-4.5 g/L
0.9-4.5 g/L
Normal range
Immunoglobulin A (IgA)
Immunoglobulin A (IgA)
Immunoglobulin A (IgA) is an antibody that protects mucous membranes in the gut and respiratory tract.
Immunoglobulin A (IgA)
Normal range
0.9-4.5 g/L
Normal range
0.9-4.5 g/L
0.9-4.5 g/L
Normal range
Immunoglobulin A (IgA)
Dr. Jack Devin
MBBS
Your Body's First Line of Defence
Your Body's First Line of Defence
IgA is your immune system’s guardian at the gates—standing watch where your body meets the outside world. Found primarily in mucous membranes like the mouth, nose, lungs, gut, and urinary tract, this specialised antibody plays a frontline role in protecting your body from invaders.
Unlike other antibodies (like IgG or IgM) that circulate mainly in your bloodstream, IgA specialises in defending surface barriers, where most infections begin. When your IgA levels are optimal, you're less likely to deal with recurrent infections, food sensitivities, or chronic gut inflammation. But when they're off—too low or too high—it can signal deeper issues in your immune balance.
IgA is your immune system’s guardian at the gates—standing watch where your body meets the outside world. Found primarily in mucous membranes like the mouth, nose, lungs, gut, and urinary tract, this specialised antibody plays a frontline role in protecting your body from invaders.
Unlike other antibodies (like IgG or IgM) that circulate mainly in your bloodstream, IgA specialises in defending surface barriers, where most infections begin. When your IgA levels are optimal, you're less likely to deal with recurrent infections, food sensitivities, or chronic gut inflammation. But when they're off—too low or too high—it can signal deeper issues in your immune balance.
When IgA Levels Are Too Low
When IgA Levels Are Too Low
When IgA Levels Are Too Low
Discover how insufficient IgA leaves your mucosal barriers vulnerable and why you might be catching every bug that comes your way.
Read more
When IgA Levels Are Too High
When IgA Levels Are Too High
When IgA Levels Are Too High
Learn why elevated IgA often signals chronic inflammation or autoimmune activity that needs attention.
Read more
What Influences Your IgA Levels?
What Influences Your IgA Levels?
What Influences Your IgA Levels?
From stress and infections to genetic factors, understand what can strengthen or weaken your body's primary protective barrier.
Read more
Understanding Your Results
Understanding Your Results
Understanding Your Results
Decode your blood test numbers and know exactly what your IgA levels reveal about your immune function and overall health.
Read more
When IgA Levels Are Too Low
Transiently low or borderline IgA levels are not likely to be clinically significant.
Significantly low IgA levels, known as selective IgA deficiency, leave your mucosal surfaces poorly defended against invading pathogens. This is the most common primary immunodeficiency, affecting roughly 1 in 500–700 people, though many don’t realise they have it until they experience recurring health issues.
With insufficient IgA protecting your barriers, bacteria, viruses, and other pathogens can more easily establish infections in your respiratory tract, digestive system, and other mucosal areas. This creates a pattern of vulnerability that can significantly impact your quality of life.
Common symptoms include:
Frequent respiratory infections (sinusitis, bronchitis, pneumonia)
Chronic digestive issues (diarrhoea, bloating, food sensitivities)
Recurrent ear infections, especially in children
Persistent skin infections or slow wound healing
Increased susceptibility to autoimmune conditions
Many people with low IgA describe feeling like they “catch everything going around” or take longer to recover from illnesses. In the gut, IgA normally prevents harmful bacteria from crossing the intestinal lining—without it, you may develop food intolerances.
Low IgA can also contribute to more serious complications, including higher risk of certain autoimmune diseases, chronic inflammatory bowel conditions, and—in rare cases—severe systemic infections.
When IgA Levels Are Too Low
Transiently low or borderline IgA levels are not likely to be clinically significant.
Significantly low IgA levels, known as selective IgA deficiency, leave your mucosal surfaces poorly defended against invading pathogens. This is the most common primary immunodeficiency, affecting roughly 1 in 500–700 people, though many don’t realise they have it until they experience recurring health issues.
With insufficient IgA protecting your barriers, bacteria, viruses, and other pathogens can more easily establish infections in your respiratory tract, digestive system, and other mucosal areas. This creates a pattern of vulnerability that can significantly impact your quality of life.
Common symptoms include:
Frequent respiratory infections (sinusitis, bronchitis, pneumonia)
Chronic digestive issues (diarrhoea, bloating, food sensitivities)
Recurrent ear infections, especially in children
Persistent skin infections or slow wound healing
Increased susceptibility to autoimmune conditions
Many people with low IgA describe feeling like they “catch everything going around” or take longer to recover from illnesses. In the gut, IgA normally prevents harmful bacteria from crossing the intestinal lining—without it, you may develop food intolerances.
Low IgA can also contribute to more serious complications, including higher risk of certain autoimmune diseases, chronic inflammatory bowel conditions, and—in rare cases—severe systemic infections.
When IgA Levels Are Too Low
Transiently low or borderline IgA levels are not likely to be clinically significant.
Significantly low IgA levels, known as selective IgA deficiency, leave your mucosal surfaces poorly defended against invading pathogens. This is the most common primary immunodeficiency, affecting roughly 1 in 500–700 people, though many don’t realise they have it until they experience recurring health issues.
With insufficient IgA protecting your barriers, bacteria, viruses, and other pathogens can more easily establish infections in your respiratory tract, digestive system, and other mucosal areas. This creates a pattern of vulnerability that can significantly impact your quality of life.
Common symptoms include:
Frequent respiratory infections (sinusitis, bronchitis, pneumonia)
Chronic digestive issues (diarrhoea, bloating, food sensitivities)
Recurrent ear infections, especially in children
Persistent skin infections or slow wound healing
Increased susceptibility to autoimmune conditions
Many people with low IgA describe feeling like they “catch everything going around” or take longer to recover from illnesses. In the gut, IgA normally prevents harmful bacteria from crossing the intestinal lining—without it, you may develop food intolerances.
Low IgA can also contribute to more serious complications, including higher risk of certain autoimmune diseases, chronic inflammatory bowel conditions, and—in rare cases—severe systemic infections.
When IgA Levels Are Too High
Elevated IgA levels typically indicate that your immune system is working overtime, often in response to chronic inflammation, persistent infection, or autoimmune activity. Unlike IgA deficiency, high levels reflect an active immune response rather than a lack of antibody.
Symptoms associated with elevated IgA often relate to the underlying condition causing the elevation rather than the high IgA itself. These might include persistent fatigue, joint pain or stiffness, digestive symptoms like abdominal pain or altered bowel habits, skin rashes or other inflammatory skin conditions, and recurring fevers or general feeling of being unwell.
A key example is IgA nephropathy (Berger’s disease), where IgA immune complexes deposit in the kidney’s filtering units, leading to blood in the urine, proteinuria, and progressive kidney damage if untreated.
When IgA Levels Are Too High
Elevated IgA levels typically indicate that your immune system is working overtime, often in response to chronic inflammation, persistent infection, or autoimmune activity. Unlike IgA deficiency, high levels reflect an active immune response rather than a lack of antibody.
Symptoms associated with elevated IgA often relate to the underlying condition causing the elevation rather than the high IgA itself. These might include persistent fatigue, joint pain or stiffness, digestive symptoms like abdominal pain or altered bowel habits, skin rashes or other inflammatory skin conditions, and recurring fevers or general feeling of being unwell.
A key example is IgA nephropathy (Berger’s disease), where IgA immune complexes deposit in the kidney’s filtering units, leading to blood in the urine, proteinuria, and progressive kidney damage if untreated.
When IgA Levels Are Too High
Elevated IgA levels typically indicate that your immune system is working overtime, often in response to chronic inflammation, persistent infection, or autoimmune activity. Unlike IgA deficiency, high levels reflect an active immune response rather than a lack of antibody.
Symptoms associated with elevated IgA often relate to the underlying condition causing the elevation rather than the high IgA itself. These might include persistent fatigue, joint pain or stiffness, digestive symptoms like abdominal pain or altered bowel habits, skin rashes or other inflammatory skin conditions, and recurring fevers or general feeling of being unwell.
A key example is IgA nephropathy (Berger’s disease), where IgA immune complexes deposit in the kidney’s filtering units, leading to blood in the urine, proteinuria, and progressive kidney damage if untreated.
What Influences Your IgA Levels?
Factors That Can Lower IgA
Several conditions and factors can reduce your IgA production:
Genetic defects affecting IgA production (selective IgA deficiency is often inherited)
Immunosuppressive medications, chemotherapy agents, and long-term corticosteroid use
Coeliac disease, which damages the intestinal lining where much IgA is produced
Primary immunodeficiency disorders
Chronic kidney or liver disease
Chronic stress which suppresses immune function
Severe malnutrition or protein deficiency
Some infections that can temporarily suppress IgA production
Age is another important factor, as IgA levels are naturally lower in infants and gradually increase throughout childhood, reaching adult levels by adolescence.
Factors That Can Raise IgA
Various conditions can elevate IgA levels:
Chronic liver disease, particularly alcoholic liver disease
Inflammatory bowel diseases like Crohn's disease or ulcerative colitis
Chronic infections, especially those affecting mucosal surfaces
Autoimmune conditions such as rheumatoid arthritis or lupus
IgA nephropathy and other kidney diseases
Some cancers, particularly those affecting immune system cells
Chronic alcohol consumption
Lifestyle factors matter too—regular moderate exercise and effective stress management may help maintain healthy levels, whilst chronic alcohol consumption is strongly linked to elevated IgA.
What Influences Your IgA Levels?
Factors That Can Lower IgA
Several conditions and factors can reduce your IgA production:
Genetic defects affecting IgA production (selective IgA deficiency is often inherited)
Immunosuppressive medications, chemotherapy agents, and long-term corticosteroid use
Coeliac disease, which damages the intestinal lining where much IgA is produced
Primary immunodeficiency disorders
Chronic kidney or liver disease
Chronic stress which suppresses immune function
Severe malnutrition or protein deficiency
Some infections that can temporarily suppress IgA production
Age is another important factor, as IgA levels are naturally lower in infants and gradually increase throughout childhood, reaching adult levels by adolescence.
Factors That Can Raise IgA
Various conditions can elevate IgA levels:
Chronic liver disease, particularly alcoholic liver disease
Inflammatory bowel diseases like Crohn's disease or ulcerative colitis
Chronic infections, especially those affecting mucosal surfaces
Autoimmune conditions such as rheumatoid arthritis or lupus
IgA nephropathy and other kidney diseases
Some cancers, particularly those affecting immune system cells
Chronic alcohol consumption
Lifestyle factors matter too—regular moderate exercise and effective stress management may help maintain healthy levels, whilst chronic alcohol consumption is strongly linked to elevated IgA.
What Influences Your IgA Levels?
Factors That Can Lower IgA
Several conditions and factors can reduce your IgA production:
Genetic defects affecting IgA production (selective IgA deficiency is often inherited)
Immunosuppressive medications, chemotherapy agents, and long-term corticosteroid use
Coeliac disease, which damages the intestinal lining where much IgA is produced
Primary immunodeficiency disorders
Chronic kidney or liver disease
Chronic stress which suppresses immune function
Severe malnutrition or protein deficiency
Some infections that can temporarily suppress IgA production
Age is another important factor, as IgA levels are naturally lower in infants and gradually increase throughout childhood, reaching adult levels by adolescence.
Factors That Can Raise IgA
Various conditions can elevate IgA levels:
Chronic liver disease, particularly alcoholic liver disease
Inflammatory bowel diseases like Crohn's disease or ulcerative colitis
Chronic infections, especially those affecting mucosal surfaces
Autoimmune conditions such as rheumatoid arthritis or lupus
IgA nephropathy and other kidney diseases
Some cancers, particularly those affecting immune system cells
Chronic alcohol consumption
Lifestyle factors matter too—regular moderate exercise and effective stress management may help maintain healthy levels, whilst chronic alcohol consumption is strongly linked to elevated IgA.
Understanding Your Results
IgA levels are measured in grams per litre (g/L) in serum:
Low: < 0.9 g/L
Normal: 0.9–4.5 g/L
High: > 4.5 g/L
However, reference ranges can vary slightly between laboratories, so always interpret your results in context with your symptoms and other test findings.
Your IgA results should be evaluated alongside your clinical symptoms and other immune markers. If you have low IgA but normal levels of other antibodies like IgG and IgM, you may have selective IgA deficiency. If multiple antibody types are low, this might suggest a more comprehensive immunodeficiency disorder.
It's important to note that IgA levels can fluctuate based on recent infections, stress levels, and overall health status. A single abnormal result may warrant retesting after a few weeks, particularly if you've been unwell recently.
Your healthcare provider may also recommend additional tests such as IgA subtype analysis, tests for specific antibody responses, or assessment of other immune system components to get a complete picture of your immune function and determine the most appropriate treatment approach.
Understanding Your Results
IgA levels are measured in grams per litre (g/L) in serum:
Low: < 0.9 g/L
Normal: 0.9–4.5 g/L
High: > 4.5 g/L
However, reference ranges can vary slightly between laboratories, so always interpret your results in context with your symptoms and other test findings.
Your IgA results should be evaluated alongside your clinical symptoms and other immune markers. If you have low IgA but normal levels of other antibodies like IgG and IgM, you may have selective IgA deficiency. If multiple antibody types are low, this might suggest a more comprehensive immunodeficiency disorder.
It's important to note that IgA levels can fluctuate based on recent infections, stress levels, and overall health status. A single abnormal result may warrant retesting after a few weeks, particularly if you've been unwell recently.
Your healthcare provider may also recommend additional tests such as IgA subtype analysis, tests for specific antibody responses, or assessment of other immune system components to get a complete picture of your immune function and determine the most appropriate treatment approach.
Understanding Your Results
IgA levels are measured in grams per litre (g/L) in serum:
Low: < 0.9 g/L
Normal: 0.9–4.5 g/L
High: > 4.5 g/L
However, reference ranges can vary slightly between laboratories, so always interpret your results in context with your symptoms and other test findings.
Your IgA results should be evaluated alongside your clinical symptoms and other immune markers. If you have low IgA but normal levels of other antibodies like IgG and IgM, you may have selective IgA deficiency. If multiple antibody types are low, this might suggest a more comprehensive immunodeficiency disorder.
It's important to note that IgA levels can fluctuate based on recent infections, stress levels, and overall health status. A single abnormal result may warrant retesting after a few weeks, particularly if you've been unwell recently.
Your healthcare provider may also recommend additional tests such as IgA subtype analysis, tests for specific antibody responses, or assessment of other immune system components to get a complete picture of your immune function and determine the most appropriate treatment approach.
The Takeaway
Immunoglobulin A is your body's specialised protector of mucosal surfaces, serving as the first line of defence against pathogens trying to enter through your respiratory tract, digestive system, and other vulnerable areas. Maintaining healthy IgA levels is crucial for preventing recurring infections and maintaining the integrity of your body's protective barriers.
Both low and high IgA levels can signal important health issues that need attention. Low levels may leave you vulnerable to frequent infections and digestive problems, whilst high levels often indicate chronic inflammation or autoimmune activity that requires investigation and management.
The encouraging news is that many conditions affecting IgA levels are treatable when properly identified. If your IgA levels are significantly abnormal, working closely with your healthcare provider to identify and address underlying causes can help restore your immune balance and improve your overall health and resilience.
The Takeaway
Immunoglobulin A is your body's specialised protector of mucosal surfaces, serving as the first line of defence against pathogens trying to enter through your respiratory tract, digestive system, and other vulnerable areas. Maintaining healthy IgA levels is crucial for preventing recurring infections and maintaining the integrity of your body's protective barriers.
Both low and high IgA levels can signal important health issues that need attention. Low levels may leave you vulnerable to frequent infections and digestive problems, whilst high levels often indicate chronic inflammation or autoimmune activity that requires investigation and management.
The encouraging news is that many conditions affecting IgA levels are treatable when properly identified. If your IgA levels are significantly abnormal, working closely with your healthcare provider to identify and address underlying causes can help restore your immune balance and improve your overall health and resilience.
The Takeaway
Immunoglobulin A is your body's specialised protector of mucosal surfaces, serving as the first line of defence against pathogens trying to enter through your respiratory tract, digestive system, and other vulnerable areas. Maintaining healthy IgA levels is crucial for preventing recurring infections and maintaining the integrity of your body's protective barriers.
Both low and high IgA levels can signal important health issues that need attention. Low levels may leave you vulnerable to frequent infections and digestive problems, whilst high levels often indicate chronic inflammation or autoimmune activity that requires investigation and management.
The encouraging news is that many conditions affecting IgA levels are treatable when properly identified. If your IgA levels are significantly abnormal, working closely with your healthcare provider to identify and address underlying causes can help restore your immune balance and improve your overall health and resilience.
References
Yel, L. (2010). Selective IgA deficiency. Journal of Clinical Immunology, 30(1), 10-16.
Suzuki, H., Kiryluk, K., Novak, J., et al. (2011). The pathophysiology of IgA nephropathy. Journal of the American Society of Nephrology, 22(10), 1795-1803.
Cunningham-Rundles, C. (2001). Physiology of IgA and IgA deficiency. Journal of Clinical Immunology, 21(5), 303-309.
NHS. Immunoglobulin deficiency. https://www.nhs.uk/conditions/immunoglobulin-deficiency/
British Society for Immunology. (2019). Clinical Guidelines for Immunoglobulin Use. Second Edition Update.
European Society for Primary Immunodeficiencies (ESID). (2020). Guidelines for the clinical management of common variable immunodeficiency disorders.
References
Yel, L. (2010). Selective IgA deficiency. Journal of Clinical Immunology, 30(1), 10-16.
Suzuki, H., Kiryluk, K., Novak, J., et al. (2011). The pathophysiology of IgA nephropathy. Journal of the American Society of Nephrology, 22(10), 1795-1803.
Cunningham-Rundles, C. (2001). Physiology of IgA and IgA deficiency. Journal of Clinical Immunology, 21(5), 303-309.
NHS. Immunoglobulin deficiency. https://www.nhs.uk/conditions/immunoglobulin-deficiency/
British Society for Immunology. (2019). Clinical Guidelines for Immunoglobulin Use. Second Edition Update.
European Society for Primary Immunodeficiencies (ESID). (2020). Guidelines for the clinical management of common variable immunodeficiency disorders.
References
Yel, L. (2010). Selective IgA deficiency. Journal of Clinical Immunology, 30(1), 10-16.
Suzuki, H., Kiryluk, K., Novak, J., et al. (2011). The pathophysiology of IgA nephropathy. Journal of the American Society of Nephrology, 22(10), 1795-1803.
Cunningham-Rundles, C. (2001). Physiology of IgA and IgA deficiency. Journal of Clinical Immunology, 21(5), 303-309.
NHS. Immunoglobulin deficiency. https://www.nhs.uk/conditions/immunoglobulin-deficiency/
British Society for Immunology. (2019). Clinical Guidelines for Immunoglobulin Use. Second Edition Update.
European Society for Primary Immunodeficiencies (ESID). (2020). Guidelines for the clinical management of common variable immunodeficiency disorders.
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