Symmetric dimethylarginine, usually shortened to SDMA, is a blood marker that rises when the kidneys filter blood less efficiently. It is made during normal protein turnover and is cleared mostly through the kidneys, so higher blood levels can point toward reduced glomerular filtration rate, or GFR. SDMA is not as commonly ordered in routine human medicine as creatinine, eGFR, BUN, cystatin C, or urine albumin testing, but it is used in specialty testing and research as an additional kidney function marker.
A high SDMA result does not diagnose one exact kidney disease by itself. It signals that kidney filtration may be lower than expected and should be interpreted with other results, health history, medications, hydration status, blood pressure, diabetes status, and urine findings. The most useful next step is usually not to focus on SDMA alone, but to confirm the pattern with standard kidney tests and address the causes that can damage kidney filtration over time.
- SDMA mainly reflects kidney filtration, because most SDMA is removed from the blood by the kidneys.
- A commonly used adult reference range is about 0.3–0.7 µmol/L, but the reporting lab’s range should be used first.
- High SDMA can occur with chronic kidney disease, acute kidney injury, diabetic kidney disease, reduced kidney blood flow, or kidney stress from medications or illness.
- SDMA may be less affected by muscle mass than creatinine, which can make it useful when creatinine looks “normal” despite concern for kidney disease.
- Follow-up usually includes creatinine with eGFR, cystatin C, BUN, electrolytes, urine albumin-to-creatinine ratio, urinalysis, and blood pressure assessment.
- Urgent medical care is needed if abnormal kidney markers occur with very low urine output, severe weakness, confusion, chest pain, shortness of breath, swelling, or dangerously high potassium.
Table of Contents
- What the SDMA Test Measures
- SDMA Normal Range and Units
- What High SDMA Means
- SDMA Compared With Other Kidney Tests
- Causes of High SDMA
- Follow-Up After Abnormal SDMA
- How to Prepare and Avoid Misleading Results
- How to Protect Kidney Function
What the SDMA Test Measures
SDMA is a methylated form of the amino acid arginine. Your body makes it during normal cell and protein turnover. When proteins that contain methylated arginine are broken down, SDMA is released into the bloodstream. The kidneys then remove most of it through filtration.
That makes SDMA different from many general blood markers. It is not a vitamin, hormone, electrolyte, enzyme, or waste product from muscle breakdown. It is a small circulating molecule that tends to accumulate when kidney filtration falls.
In kidney testing, “filtration” usually refers to how well the glomeruli work. Glomeruli are tiny filtering units inside the kidneys. They help remove waste products and extra fluid while keeping needed proteins and blood cells in the bloodstream. A decline in glomerular filtration can happen slowly over months to years, as in chronic kidney disease, or quickly over hours to days, as in acute kidney injury.
SDMA is sometimes described as an endogenous kidney marker. “Endogenous” means the body makes it naturally. A marker like this can be useful because it does not require an injected substance to measure filtration directly. Direct GFR tests can be more precise, but they are more complex and are not used for routine screening.
In everyday care, most kidney assessment still centers on creatinine, estimated glomerular filtration rate, urine albumin, urinalysis, and electrolytes. SDMA can add context, especially when creatinine may be misleading because of unusually low muscle mass, very high muscle mass, aging, chronic illness, or other factors that affect creatinine production. For a broader look at common kidney markers, a kidney function blood test panel explains how creatinine, BUN, eGFR, and electrolytes fit together.
SDMA should not be treated as a stand-alone diagnosis. A high result is a signal to look more closely at kidney filtration, not a final answer about the cause.
SDMA Normal Range and Units
A typical adult SDMA reference range is roughly 0.3–0.7 µmol/L. Some laboratories may report SDMA in µg/dL, ng/mL, or nmol/L instead. Because assays and calibration methods differ, the best “normal range” is always the reference interval printed on the lab report.
A helpful conversion is:
1 µmol/L of SDMA is about 20.2 µg/dL, or about 202 ng/mL.
Using that conversion, an SDMA of 0.70 µmol/L is about 14 µg/dL. This is why an upper limit near 0.7 µmol/L and an upper limit near 14 µg/dL often refer to a similar concentration.
| SDMA result | Approximate equivalent | Common interpretation |
|---|---|---|
| About 0.3–0.5 µmol/L | About 6–10 µg/dL | Often comfortably within expected range, if other kidney markers are normal |
| About 0.5–0.7 µmol/L | About 10–14 µg/dL | Often still within range, but trends may matter in people at kidney risk |
| Above about 0.7 µmol/L | Above about 14 µg/dL | Often considered elevated, depending on the lab’s reference interval |
| Clearly above 1.0 µmol/L | Above about 20 µg/dL | More concerning for reduced filtration, especially if eGFR is low or urine tests are abnormal |
These ranges should be used as a general guide, not a diagnosis. A person with an SDMA slightly above the lab range may have early kidney filtration decline, but the result could also reflect temporary kidney stress, dehydration, recent illness, or lab-to-lab variation. A person with a “normal” SDMA can still have kidney disease if urine albumin is high, blood pressure is damaging the kidneys, or structural kidney disease is present.
Why the lab range matters
SDMA can be measured by liquid chromatography-tandem mass spectrometry, immunoassay, or other laboratory methods. These methods may not give perfectly identical results. That is one reason serial testing is easiest to interpret when the same lab and the same method are used.
It also helps to compare SDMA with results from the same date. A single SDMA number has less meaning than the full pattern: eGFR, creatinine, cystatin C, BUN, urine albumin, urinalysis, potassium, bicarbonate, blood pressure, and recent health events.
Can SDMA be too low?
Low SDMA is usually not the main clinical concern. A low or low-normal result generally suggests that SDMA is not accumulating in the bloodstream. Unlike sodium, potassium, calcium, or glucose, SDMA does not usually have a well-established “deficiency” state. If SDMA is unexpectedly low, the issue is more often analytical variation, unit confusion, or interpretation in the context of other markers.
What High SDMA Means
High SDMA usually means the kidneys may not be clearing SDMA from the blood efficiently. Since SDMA is removed mainly by the kidneys, an elevated level can point toward reduced kidney filtration.
The most common interpretation is reduced GFR. GFR stands for glomerular filtration rate, which estimates how much blood the kidneys filter per minute. In routine care, GFR is usually estimated from creatinine, cystatin C, or both. SDMA is not the standard staging marker for chronic kidney disease, but it may rise in patterns that track with lower eGFR.
A high SDMA result becomes more convincing when it appears with one or more of these findings:
- Low eGFR
- High creatinine
- High cystatin C
- High BUN or urea
- Albumin or protein in the urine
- Blood in the urine
- High potassium
- Low bicarbonate or abnormal CO2
- High blood pressure
- Swelling in the legs, ankles, or around the eyes
- Reduced urine output
When SDMA is high but creatinine and eGFR are normal, the result should be repeated or confirmed with additional tests rather than ignored. Creatinine can look normal in people with low muscle mass because creatinine comes from muscle metabolism. Older adults, people with frailty, people with chronic illness, and people with limb loss may have deceptively low creatinine. In those situations, SDMA and cystatin C testing may provide a useful second view of filtration.
High SDMA does not tell you where kidney damage is occurring. It does not separate glomerular disease from tubule injury, kidney artery problems, obstruction, dehydration, or medication-related kidney stress. It also does not replace urine testing. Urine albumin can show kidney barrier injury even when filtration markers are still near normal.
How high is concerning?
Any SDMA result above the laboratory’s upper reference limit deserves review. The level of concern depends on the size of the increase and the rest of the kidney picture.
A mild increase may call for repeat testing, medication review, hydration assessment, and urine albumin testing. A larger increase, a rising trend, or an elevated SDMA with low eGFR needs more direct kidney evaluation. If abnormal SDMA appears with high potassium, severe acidosis, fluid overload, or very low urine output, the situation may be urgent.
SDMA Compared With Other Kidney Tests
SDMA is best understood as one part of a kidney marker group. It overlaps with creatinine, cystatin C, BUN, and eGFR, but it is not identical to any of them.
Creatinine is the most common blood marker used to estimate kidney filtration. It is inexpensive, widely available, and included in many chemistry panels. The main limitation is that creatinine depends heavily on muscle mass. A muscular person may have a higher creatinine without kidney disease, while a frail person may have a normal creatinine despite reduced kidney function. A creatinine blood test is still essential, but it is strongest when interpreted with eGFR and clinical context.
eGFR is a calculated estimate of filtration, usually based on creatinine, cystatin C, or both. It is the main number used to classify chronic kidney disease stages. An eGFR test is more clinically established than SDMA for CKD staging and follow-up.
Cystatin C is a protein made by most cells and cleared by the kidneys. It is less dependent on muscle mass than creatinine, although inflammation, thyroid status, steroids, obesity, and smoking can influence it in some cases. Cystatin C is often used when creatinine-based eGFR may be inaccurate.
BUN, or blood urea nitrogen, reflects urea nitrogen in the blood. Urea comes from protein metabolism and is influenced by kidney function, protein intake, hydration, gastrointestinal bleeding, liver function, and catabolic stress. A BUN test can support kidney interpretation, but it is less specific for filtration than eGFR.
The BUN/creatinine ratio can help separate some patterns, such as dehydration or reduced kidney blood flow, from other causes of abnormal kidney markers. It is not definitive by itself, but a BUN/creatinine ratio may provide useful clues when BUN and creatinine move differently.
| Marker | Main use | Important limitation |
|---|---|---|
| SDMA | Additional marker of kidney filtration | Not yet as standardized or widely used in human routine care as eGFR |
| Creatinine | Core marker used to calculate eGFR | Affected by muscle mass, diet, and some medications |
| eGFR | Main estimate for CKD staging | Estimated, not directly measured; may be less accurate in certain body types or illnesses |
| Cystatin C | Alternative or confirmatory filtration marker | Can be affected by non-kidney factors such as inflammation or steroid use |
| BUN | Urea-related waste marker | Affected by hydration, protein intake, liver function, and bleeding in the gut |
| Urine albumin | Marker of kidney barrier injury | Can rise temporarily after exercise, fever, infection, or poor glucose control |
SDMA’s main appeal is that it may detect reduced filtration in situations where creatinine is less reliable. Its main limitation is that it is not the central marker in most kidney guidelines for humans. For that reason, a high SDMA should lead to a complete kidney evaluation instead of replacing established tests.
Causes of High SDMA
High SDMA most often reflects reduced kidney clearance, but the reason for reduced clearance can vary. Some causes are chronic and progressive. Others are temporary and reversible.
Chronic kidney disease
Chronic kidney disease, or CKD, means kidney abnormalities have lasted at least three months. CKD can involve low eGFR, albumin in the urine, abnormal urine sediment, structural kidney changes, or a kidney transplant history. SDMA may rise as filtration declines, but CKD is still usually classified with eGFR and urine albumin categories.
Common CKD causes include diabetes, high blood pressure, glomerulonephritis, polycystic kidney disease, recurrent kidney infections, long-term obstruction, and repeated kidney injury from medications or toxins.
Diabetic kidney disease
Diabetes can damage small blood vessels in the kidneys. Early diabetic kidney disease may first show up as urine albumin before eGFR falls. Over time, filtration can decline and blood markers may rise.
In a person with diabetes, high SDMA should prompt a full kidney risk review: HbA1c or glucose control, blood pressure, urine albumin-to-creatinine ratio, eGFR trend, medication list, and cardiovascular risk. Kidney protection in diabetes often depends on early action, not waiting until filtration is severely reduced.
High blood pressure and vascular disease
High blood pressure can damage the small vessels that supply the kidneys. It can also worsen existing kidney disease. Reduced kidney blood flow from heart failure, severe dehydration, kidney artery narrowing, or shock can also raise filtration markers.
This is one reason kidney markers should be interpreted with blood pressure readings and fluid status. A person with high SDMA, high blood pressure, and urine albumin needs a different evaluation than someone with high SDMA after vomiting, diarrhea, and poor fluid intake.
Acute kidney injury
Acute kidney injury, or AKI, is a sudden drop in kidney function. It may develop after dehydration, severe infection, low blood pressure, surgery, contrast dye exposure, urinary blockage, or kidney-toxic medication exposure.
AKI can be mild and reversible, but it can also become life-threatening. The urgency depends on the whole picture, including urine output, creatinine trend, potassium, bicarbonate, symptoms, and the suspected cause. Electrolytes are especially important because kidney injury can cause dangerous changes in potassium and acid-base balance. An electrolyte panel helps check sodium, potassium, chloride, and CO2/bicarbonate patterns that often matter in kidney disease.
Medication-related kidney stress
Some medications can reduce kidney filtration or increase kidney injury risk, especially during dehydration or acute illness. Examples include nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen, certain antibiotics, some antivirals, contrast agents, calcineurin inhibitors such as tacrolimus or cyclosporine, and some diuretics when fluid volume is low.
ACE inhibitors and ARBs can cause a small expected creatinine change when started, but they are also kidney-protective in many people with albuminuria and high blood pressure. They should not be stopped without medical guidance. The right response depends on why the medication is being used, how much kidney markers changed, and whether potassium is safe.
Urinary blockage
A blockage can raise kidney markers by preventing urine from draining properly. Causes include enlarged prostate, kidney stones, tumors, strictures, or severe urinary retention. Warning signs may include trouble urinating, lower belly pain, flank pain, blood in the urine, fever, or a sudden drop in urine output.
A high SDMA with symptoms of obstruction needs prompt medical assessment because relieving the blockage can prevent permanent damage.
Follow-Up After Abnormal SDMA
The right follow-up depends on how high SDMA is, whether it is rising, and whether standard kidney tests are abnormal. A mild isolated increase may need repeat testing. A high or rising result with other abnormal markers needs a more complete kidney workup.
A practical follow-up plan often includes:
- Repeat SDMA if the result is unexpected or does not match the rest of the clinical picture.
- Check creatinine with eGFR, ideally compared with previous results.
- Consider cystatin C or combined creatinine-cystatin C eGFR if muscle mass may distort creatinine.
- Measure BUN or urea to assess another waste marker.
- Check electrolytes, especially potassium and bicarbonate/CO2.
- Order urinalysis to look for blood, protein, casts, infection signs, and specific gravity.
- Check urine albumin-to-creatinine ratio, especially in diabetes, high blood pressure, or CKD risk.
- Review medications and supplements.
- Measure blood pressure accurately and repeatedly.
- Consider kidney ultrasound if obstruction, structural disease, stones, or unexplained kidney decline is suspected.
The timing matters. If SDMA is mildly high and everything else is stable, repeating tests in a few weeks to three months may be reasonable. If creatinine is rising quickly, potassium is high, urine output is falling, or symptoms are present, follow-up should happen much sooner.
When abnormal SDMA needs urgent care
Urgent evaluation is important when an abnormal kidney result appears with signs that kidney function may be dropping quickly or affecting the heart, brain, lungs, or fluid balance.
Seek urgent medical help if high SDMA or other kidney abnormalities occur with:
- Very low urine output or inability to urinate
- Severe swelling or sudden weight gain from fluid
- Shortness of breath
- Chest pain or fainting
- Confusion, severe drowsiness, or seizures
- Severe vomiting or diarrhea with dehydration
- Fever with flank pain
- Severe muscle breakdown symptoms, such as dark cola-colored urine and muscle pain
- High potassium or symptoms of heart rhythm disturbance
High potassium is one of the most time-sensitive kidney-related abnormalities because it can affect heart rhythm. If potassium is elevated along with worsening kidney markers, a high potassium blood test result should be treated as potentially urgent until a clinician confirms the risk level.
Questions to ask about your result
A useful discussion with a clinician may include these questions:
- Is my SDMA above this lab’s reference range?
- Are my creatinine, eGFR, cystatin C, BUN, and urine albumin normal?
- Has my kidney function changed compared with previous tests?
- Could dehydration, illness, exercise, or medication explain the result?
- Should I repeat the test, and when?
- Do I need urine testing or kidney imaging?
- Are any of my medications unsafe at my current kidney function?
- What blood pressure and glucose targets are appropriate for me?
These questions help shift the focus from one number to the kidney pattern that affects care.
How to Prepare and Avoid Misleading Results
Most SDMA blood tests do not require fasting unless the lab or clinician orders other tests that do. Still, consistent testing conditions make trends easier to interpret.
Good preparation usually includes staying normally hydrated, avoiding unusual high-intensity exercise right before testing, and telling the clinician about recent illness, vomiting, diarrhea, fever, infections, new medications, supplements, and imaging studies with contrast.
Do not overdrink water to “improve” the result. Excessive water intake can distort other blood and urine markers, especially sodium and urine concentration. Normal hydration is enough.
Do not stop prescribed medication before the test unless the prescribing clinician tells you to. Some kidney-related medicines affect creatinine, potassium, blood pressure, and urine albumin, but stopping them suddenly can be harmful.
Unit confusion is common
SDMA results can look very different depending on units. For example, 0.7 µmol/L and 14 µg/dL can describe nearly the same SDMA concentration. A result of “14” is not automatically worse than “0.7”; the unit changes the number.
Always check:
- The unit printed beside the result
- The lab’s reference interval
- Whether the sample was serum or plasma
- Whether the same method was used as previous tests
- Whether the result is flagged high by that lab
One abnormal value should usually be confirmed
A single abnormal SDMA result can be real, but confirmation is often wise when the result does not match the rest of the data. Kidney markers can change with acute illness, fluid balance, medications, lab variation, and timing.
A trend is more useful than a single value. For example, an SDMA that rises from 0.45 to 0.62 to 0.78 µmol/L over time may be more meaningful than one isolated result of 0.72 µmol/L after a stomach virus.
SDMA is not a home kidney score
SDMA is sometimes marketed as an early kidney marker, but it should not be used to self-diagnose CKD or self-adjust medication doses. Kidney care decisions depend on eGFR, urine albumin, electrolytes, blood pressure, diabetes status, symptoms, imaging when needed, and the pace of change.
A standard basic metabolic panel or comprehensive metabolic panel may provide essential context because it includes creatinine and several electrolytes. SDMA may add information, but it does not replace those routine tests.
How to Protect Kidney Function
The best response to high SDMA is to protect kidney filtration while the cause is being clarified. Many kidney risks are modifiable, especially high blood pressure, diabetes, medication exposures, dehydration episodes, and high cardiovascular risk.
Blood pressure control is one of the strongest kidney-protective steps. Many adults with CKD or albuminuria need careful blood pressure management, often with medications that protect the kidney’s filtering units. The right target depends on age, frailty, albuminuria, cardiovascular risk, and medication tolerance.
Diabetes control also matters. Large swings in glucose and long-term hyperglycemia can damage kidney vessels. People with diabetes often need regular urine albumin-to-creatinine ratio testing even when eGFR is normal, because albuminuria can appear before filtration falls.
Medication review is another major step. Avoiding unnecessary NSAID use is especially important for people with CKD, dehydration risk, heart failure, cirrhosis, older age, or use of ACE inhibitors, ARBs, or diuretics. Some medications need dose adjustment when eGFR falls. Others need closer potassium or creatinine monitoring.
Lifestyle changes can support kidney and blood vessel health:
- Keep blood pressure in the recommended range.
- Manage diabetes with individualized glucose targets.
- Avoid smoking and nicotine exposure.
- Maintain a kidney-appropriate protein intake rather than extreme high-protein dieting.
- Limit excess sodium, especially with high blood pressure or swelling.
- Stay normally hydrated during illness and heat exposure.
- Treat urinary obstruction or recurrent infections promptly.
- Discuss contrast dye risk before imaging if kidney function is reduced.
- Keep follow-up appointments when eGFR or urine albumin is abnormal.
Diet should match the person’s kidney stage and lab pattern. Someone with normal potassium does not need the same diet as someone with high potassium. Someone with kidney stones may need different advice than someone with diabetic kidney disease. People with moderate to advanced CKD should avoid making major protein, potassium, phosphorus, or supplement changes without guidance.
SDMA can be useful as an early warning signal, but kidney protection works best when it is tied to confirmed risks. A high SDMA result should lead to a clear plan: confirm kidney function, identify the cause, reduce kidney stress, and follow the trend over time.
References
- Symmetric dimethylarginine as a biomarker of renal impairment after a decade of follow-up 2025 (Research Article)
- The Role of Serum Symmetric Dimethylarginine (SDMA) As Endogenous Biomarker of Renal Impairment in Correlation with Severity and Different Stages of Diabetic Kidney Disease 2025 (Research Article)
- Dimethylarginines in pediatric CKD: clinical utility of ADMA and SDMA as biomarkers 2025 (Research Article)
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease 2024 (Guideline)
- Asymmetric and Symmetric Dimethylarginines as Renal Function Parameters in Pediatric Nephropathies 2022 (Review)
- Symmetric dimethylarginine (SDMA) as endogenous marker of renal function – A meta-analysis 2006 (Meta-analysis)
Disclaimer
SDMA results should be interpreted by a qualified healthcare professional together with standard kidney tests, urine results, medications, symptoms, and medical history. A high SDMA result can suggest reduced kidney filtration, but it does not identify the exact cause or replace urgent care when symptoms of acute kidney injury, fluid overload, or high potassium are present.
