What does "Qn" mean in Immunoglobulin M, Qn, Serum?

Qn is short for quantitative. It means the result is reported as an actual number — a concentration in mg/dL — rather than as positive or negative. It signals that this test measures how much IgM is present, not whether a particular antibody is detectable.

Is Immunoglobulin M, Qn, Serum the same as an IgM antibody test?

No — this is a frequent source of confusion in this page's query data. This test adds all of your IgM together. A pathogen IgM test — for a virus, for Lyme, for a suspected infection — measures IgM directed at one specific target and may be reported as positive or negative. It may be used when evaluating infection, but it must be interpreted according to that specific assay. These are different measurements: a total IgM result cannot tell whether a target-specific IgM is positive, and a positive target-specific result does not establish that total IgM is high.

What is a normal IgM level?

Reference intervals differ by age and by sex, and for IgM the adult difference between men and women is substantial. Labcorp reports 20–172 mg/dL for men aged 20–70 and 26–217 mg/dL for women over 19, with different intervals at every stage of childhood. Other laboratories publish their own intervals, so the range printed on your own report is the one that applies to your result.

What does a high IgM mean?

It means your total IgM concentration is above the reference interval for your age, sex and laboratory. A high total IgM can reflect a broad immune response — IgM is produced early when the body meets something new — or an abnormal cell line. The number alone cannot distinguish the two. It is interpreted with your symptoms, your other immunoglobulins, and any further testing your clinician considers appropriate.

Can normal total IgM rule out a monoclonal protein?

No conclusion about a monoclonal protein should be drawn from total IgM alone. When one is clinically suspected, clinicians may use tests such as serum protein electrophoresis and immunofixation to investigate it.

What does a low IgM mean?

It means your total IgM concentration is below the reference interval for your age, sex and laboratory. It can reflect reduced antibody production, a medication effect, or protein loss through the kidneys or gut. It is generally interpreted alongside IgG and IgA rather than on its own, and recurrent infections make the finding more clinically important.

Why was my IgM measured together with IgG and IgA?

Because the three classes are read as a set. What IgG and IgA are doing alongside IgM helps shape the interpretation — a fall across all three points somewhere different from an isolated low IgM, and the pattern across classes is more informative than any single value.

Can I raise or lower my IgM with diet or supplements?

No. Total IgM reflects what your plasma cells are producing and what your body is losing or clearing, and it is not meaningfully modifiable by diet, exercise or supplementation. Where it is treated, treatment is directed at the underlying cause.

Immunoglobulin M, Qn, Serum: What a High or Low Total IgM Means

Serum

Other names: Total IgM (mg/dL), ImmunogM, IgM, Total, Quant, IMMUNOGLOBULIN M, SERUM), WarningHighImmunoglobulin M, Qn, Serum

Optimal Result: 26 - 217 mg/dL, or 0.26 - 2.17 g/L.

Immune System

From Healthmatters.io Team and reviewed by HealthMatters Editorial Team

Written on July 28, 2026 | Last updated Updated on July 28, 2026

Lab Results Explained and Tracked

In one sentence

Immunoglobulin M, Qn, Serum reports how much IgM antibody protein is in your blood — not where it came from, and not what it is aimed at.

At a Glance

What it measures: the total concentration of IgM in serum, in mg/dL
Why it is ordered: evaluation of humoral immunity; assessment of selected immune or plasma-cell disorders, including monitoring of Waldenström macroglobulinemia
How it is measured: immunoturbidimetry on serum, from a red-top or gel-barrier tube
Reference interval: age- and sex-specific, with a wide adult male/female difference — see the table below
Read with: IgG, IgA, total globulin, albumin-to-globulin ratio
What it cannot do: identify the source of an increase, identify what any antibody targets, or diagnose cancer on its own

What Immunoglobulin M, Qn, Serum measures

Immunoglobulin M is the first antibody your immune system produces when it meets something new. It is the largest antibody class — a pentamer, five units joined together. Unlike IgG, IgM does not cross the placenta appreciably. Target-specific IgM produced by a newborn may therefore contribute to the evaluation of certain congenital infections; total IgM does not identify a particular infection.

This test measures the total concentration of that protein in serum. It does not separate IgM by what produced it or by what it recognizes.

What "Qn" means on your report

"Qn" is short for quantitative. It signals that the result is a number — an actual concentration — rather than a positive/negative or reactive/non-reactive finding.

"IgM" on a mycoplasma, hepatitis, EBV, or Lyme report refers to IgM directed at that specific target. Such a result may be used when evaluating infection, but it has to be interpreted according to that specific assay — timing, persistence, and cross-reactivity all vary. Immunoglobulin M, Qn, Serum is not that test. It counts all of your IgM together, regardless of target. A person with a high total IgM and a person with a positive mycoplasma IgM are holding two different measurements.

Reference ranges by age and sex

IgM intervals shift through childhood and differ substantially between adult men and women. A single figure presented as "normal" cannot serve all of these rows.

Age	Male (mg/dL)	Female (mg/dL)
0–10 days	3–10	1–19
11 days–6 months	18–91	18–96
7–11 months	27–112	32–127
1–3 years	39–146	45–163
4–6 years	40–152	51–181
7–9 years	37–151	51–187
10–11 years	36–153	53–194
12–13 years	36–156	57–209
14–15 years	35–163	59–220
16–19 years	35–168	58–230
Adult	20–172 (20–70 y); 15–143 (>70 y)	26–217 (>19 y)

These are Labcorp's intervals for test 001792. Other laboratories set their own using their own instruments and populations, so the range printed on your own report is the one that applies to you. Note how far apart the adult columns sit: a woman's upper limit is 217, a man's is 172. A single "optimal" band cannot serve both.

Two people with the same number

Two adults both have a total IgM of 210 mg/dL.

The first is a 30-year-old woman. Her reference interval tops out at 217, so this result is within range — unremarkable.

The second is a 40-year-old man. His interval tops out at 172, so the same number is clearly above his reference interval and warrants a look at why.

Identical value, opposite interpretation — decided entirely by which row applies. This is why a universal band does real harm for IgM specifically, and why the age/sex table above is the most important thing on the page.

What this test cannot tell you

Whether an increase is broad or clonal. It reports one figure for both.
What any of your antibodies target. A total IgM cannot tell you whether a mycoplasma, EBV, or Lyme IgM test would come back positive.
Whether a monoclonal protein is present. No conclusion about a monoclonal protein should be drawn from the total alone; electrophoresis and immunofixation are what investigate one.
Whether a recent infection is the cause. A raised total is consistent with a broad immune response but does not establish infection; a target-specific test speaks to that question.
Whether your immune system is "strong." IgM is one component of one arm of immunity.

Reading IgM alongside your other results

Total IgM becomes far more informative in company. The pattern across the immunoglobulin classes and the protein fractions helps narrow the picture.

IgM	IgG and IgA	Globulin / A:G ratio	Pattern commonly considered
High	Normal	Normal or mildly high	A reactive rise — the picture seen with a broad immune response, including infection or inflammation
High	Both also high	Globulin high, A:G low	A broad increase across classes — chronic infection, autoimmunity, liver disease
High	One or both low	Globulin high	Uninvolved classes suppressed — raises the question of a single clone
Low	Both also low	Globulin low	Reduced antibody production across classes
Low	Both normal	Globulin low, albumin low	Raises loss or suppression rather than underproduction

This table describes patterns clinicians commonly consider. It is not a diagnostic algorithm, no row determines what happens next, and none of it substitutes for your clinician's reading of your full picture.

Read together with

IgG and IgA — the other two quantitative immunoglobulin classes; IgM is almost always run as part of that set
Total globulin and the albumin/globulin ratio — often where an immunoglobulin abnormality is first noticed
Serum protein electrophoresis — the test that separates broad from clonal increases
A target-specific IgM (for a suspected infection) — a different test answering a different question, interpreted by its own assay
Current medications — corticosteroids and B-cell-depleting therapies lower IgM

Common interpretation mistakes

Reading a positive pathogen IgM as a high total IgM. Different tests entirely — a frequent source of confusion in this page's query data.
Reading a raised total as a cancer finding. A raised total can accompany inflammatory, infectious, liver, immune, or blood disorders, and the total cannot distinguish among them.
Drawing a conclusion about a monoclonal protein from the total. The total cannot establish or rule one out; electrophoresis and immunofixation are what investigate it.
Comparing an adult result to a child's interval, or a man's to a woman's. For IgM the sex gap is wide enough to flip the interpretation.
Assuming an out-of-range result triggers a specific next test. What follows depends on the clinical picture, not the number.
Trying to change the number directly. Where treatment exists, it addresses the cause.

Questions your doctor may ask

Have you had a recent infection, or symptoms of one — fever, fatigue, swollen glands?
How often do you get infections, and how severe are they?
Are you taking corticosteroids, rituximab, or another immune-suppressing medication?
Any known liver disease, autoimmune condition, or symptoms suggesting one?
Any protein in the urine, swelling, or chronic diarrhea?
Was a target-specific IgM — for a particular virus or infection — also ordered?

Things that can affect the result

Age and sex, as the table shows — with a substantial adult difference between men and women. Corticosteroids and B-cell-depleting therapies such as rituximab, which lower IgM. Protein loss through the kidneys or gut. And a handling issue worth naming: samples containing macroglobulins or cryoglobulins should be drawn and held at body temperature, and samples suspected of containing cold agglutinins should not be refrigerated before the serum is separated. Excessive lipemia is a cause for sample rejection.

Clinical pearls

IgM is produced early in a new immune response, so a reactive rise is one possible explanation for a raised total — but the total cannot confirm a cause, and it cannot separate a broad rise from a clone.
IgM is characteristically elevated in primary biliary cholangitis.
On the low side, what IgG and IgA are doing is often more informative than how far IgM has fallen.
No conclusion about a monoclonal protein should be drawn from total IgM alone; electrophoresis and immunofixation can help detect and characterize one.
IgG is transported across the placenta and IgM is not. A newborn's own target-specific IgM may contribute to evaluating certain congenital infections; total IgM does not identify one.

Clinical Takeaway

Total IgM tells you how much IgM antibody protein is present. It cannot tell you whether an increase is a broad immune response or a single clone, and it cannot tell you what any antibody targets — those questions need other tests. Bring the number to your clinician together with your IgG, IgA, globulin, and albumin results; that combination is what carries the information.

If you remember only one thing: total IgM adds every IgM antibody into one concentration. A high value cannot distinguish a broad immune response from a clone, and no conclusion about a monoclonal protein should be drawn from the total alone.

Bottom line. An out-of-range Immunoglobulin M, Qn, Serum result is a reason for a conversation, not a conclusion. What happens next depends on your symptoms, your other results, your medications, and your history — not on the number by itself.

This page is not medical advice. Reference intervals differ between laboratories, and only your own clinician can interpret your result in the context of your history, symptoms, and other findings.

FAQ about Immunoglobulin M, Qn, Serum

What does "Qn" mean in Immunoglobulin M, Qn, Serum?

Qn is short for quantitative. It means the result is reported as an actual number — a concentration in mg/dL — rather than as positive or negative. It signals that this test measures how much IgM is present, not whether a particular antibody is detectable.
Is Immunoglobulin M, Qn, Serum the same as an IgM antibody test?

No — this is a frequent source of confusion in this page's query data. This test adds all of your IgM together. A pathogen IgM test — for a virus, for Lyme, for a suspected infection — measures IgM directed at one specific target and may be reported as positive or negative. It may be used when evaluating infection, but it must be interpreted according to that specific assay. These are different measurements: a total IgM result cannot tell whether a target-specific IgM is positive, and a positive target-specific result does not establish that total IgM is high.
What is a normal IgM level?

Reference intervals differ by age and by sex, and for IgM the adult difference between men and women is substantial. Labcorp reports 20–172 mg/dL for men aged 20–70 and 26–217 mg/dL for women over 19, with different intervals at every stage of childhood. Other laboratories publish their own intervals, so the range printed on your own report is the one that applies to your result.
What does a high IgM mean?

It means your total IgM concentration is above the reference interval for your age, sex and laboratory. A high total IgM can reflect a broad immune response — IgM is produced early when the body meets something new — or an abnormal cell line. The number alone cannot distinguish the two. It is interpreted with your symptoms, your other immunoglobulins, and any further testing your clinician considers appropriate.
Does a high IgM mean cancer?

A high total IgM does not by itself mean cancer. It can rise with inflammatory or infectious conditions and with certain liver, immune, or blood disorders. The result must be interpreted with your symptoms, your other immunoglobulins, and any additional testing your clinician considers appropriate. If a monoclonal protein is suspected, clinicians may use electrophoresis, immunofixation, and other testing to look into it.
Can normal total IgM rule out a monoclonal protein?

No conclusion about a monoclonal protein should be drawn from total IgM alone. When one is clinically suspected, clinicians may use tests such as serum protein electrophoresis and immunofixation to investigate it.
What does a low IgM mean?

It means your total IgM concentration is below the reference interval for your age, sex and laboratory. It can reflect reduced antibody production, a medication effect, or protein loss through the kidneys or gut. It is generally interpreted alongside IgG and IgA rather than on its own, and recurrent infections make the finding more clinically important.
Why was my IgM measured together with IgG and IgA?

Because the three classes are read as a set. What IgG and IgA are doing alongside IgM helps shape the interpretation — a fall across all three points somewhere different from an isolated low IgM, and the pattern across classes is more informative than any single value.
Can anything make my IgM result inaccurate?

Handling can. Samples containing macroglobulins or cryoglobulins should be drawn and held at body temperature, and samples suspected of containing cold agglutinins should not be refrigerated before the serum is separated, because mishandling can distort the result. Excessive lipemia is a cause for sample rejection.
Can I raise or lower my IgM with diet or supplements?

No. Total IgM reflects what your plasma cells are producing and what your body is losing or clearing, and it is not meaningfully modifiable by diet, exercise or supplementation. Where it is treated, treatment is directed at the underlying cause.

Lab Results Explained and Tracked

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What does it mean if your Immunoglobulin M, Qn, Serum result is too high?

A high result means your total IgM concentration is above the reference interval for your age, sex, and laboratory. A raised total IgM can reflect a broad immune response — IgM is produced early when the body meets something new — and can also accompany inflammatory or infectious conditions and certain liver, immune, or blood disorders, including primary biliary cholangitis and a plasma-cell or lymphoproliferative disorder such as Waldenström macroglobulinemia.

The number alone cannot show whether the increase is a broad reactive one or the product of a single abnormal cell line. If a monoclonal protein is suspected, clinicians may use electrophoresis, immunofixation, and other testing to look into it. Total IgM by itself does not diagnose cancer; the result is interpreted with your symptoms, your other immunoglobulins, and any additional testing your clinician considers appropriate.

Handling matters too: samples containing macroglobulins or cryoglobulins can read unreliably if not drawn and held at the right temperature, which is relevant when a result does not fit the clinical picture.

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What does it mean if your Immunoglobulin M, Qn, Serum result is too low?

A low result means your total IgM concentration is below the reference interval for your age, sex, and laboratory.

It is interpreted alongside IgG and IgA rather than on its own. A fall across all three classes points somewhere different from an isolated low IgM. Reduced production, a medication effect — corticosteroids, chemotherapy, and B-cell-depleting therapies such as rituximab are recognized causes — or protein loss through the kidneys or gut are among the possibilities. Recurrent infections, particularly of the respiratory and gastrointestinal tracts, make the finding more clinically important. The pattern across classes and the clinical picture are what decide its significance.

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Immunoglobulin M, Qn, Serum: What a High or Low Total IgM Means

In one sentence

At a Glance

What Immunoglobulin M, Qn, Serum measures

What "Qn" means on your report

Reference ranges by age and sex

Two people with the same number

What this test cannot tell you

Reading IgM alongside your other results

Read together with

Common interpretation mistakes

Questions your doctor may ask

Things that can affect the result

Clinical pearls

Clinical Takeaway

FAQ about Immunoglobulin M, Qn, Serum

What does "Qn" mean in Immunoglobulin M, Qn, Serum?

Is Immunoglobulin M, Qn, Serum the same as an IgM antibody test?

What is a normal IgM level?

What does a high IgM mean?

Does a high IgM mean cancer?

Can normal total IgM rule out a monoclonal protein?

What does a low IgM mean?

Why was my IgM measured together with IgG and IgA?

Can anything make my IgM result inaccurate?

Can I raise or lower my IgM with diet or supplements?

All Your Lab Results. One Simple Dashboard.

What does it mean if your Immunoglobulin M, Qn, Serum result is too high?

All Your Lab Results. One Simple Dashboard.

Import, Track, and Share Your Lab Results Easily

Import, Track, and Share Your Lab Results

What does it mean if your Immunoglobulin M, Qn, Serum result is too low?

Related Biomarkers

Article Review & Sources

Bring All Your Lab Results Together — In One Place

Gather Your Lab History — and Finally Make Sense of It

Finally, Your Lab Results Organized and Clear

Advanced Plan

Unlimited Account

Pro Monthly

What's included in a Healthmatters membership

Import Lab Results from Any Source

See Your Health Timeline

Understand What Your Results Mean

Enter Your Lab Reports Yourself — Always Free Enter Your Lab Reports — Always Free

Visualize Your Results

Export Your Complete Lab History in a Single File Export Your Complete Lab History

Comprehensive Data Entry Service for Your Reports Data Entry Service for Your Reports

Securely Share With Anyone You Trust

Let Your Lab Results Tell the Full Story

Once your results are in one place, see the bigger picture — track trends over time, compare data side by side, export your full history, and share securely with anyone you trust.

Bring all your results together to compare, track progress, export your history, and share securely.

What Healthmatters Members Are Saying

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We implement proven measures to keep your data safe.

All Your Lab Results.
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