SDMA — Symmetric Dimethylarginine¶
1. What is SDMA?¶
Symmetric dimethylarginine (SDMA) is a methylated arginine derivative released into the circulation at a constant rate during protein degradation and cleared almost exclusively by renal filtration. Unlike creatinine, SDMA is not affected by muscle mass, making it a more reliable early marker of reduced glomerular filtration rate (GFR).
2. Data Card¶
| Field | Value |
|---|---|
| Biomarker | SDMA (Symmetric Dimethylarginine) |
| Full name | Symmetric dimethylarginine |
| Organ | Kidney (renal function) |
| Species | Canine, Feline |
| Specimen | Serum / Plasma |
| Method | FICT (Fluorescence Immunochromatography) |
| Analyzer | FIA680 / FIA880 |
| Unit | µg/dL |
3. Reference Range¶
| Species | Reference Range | Elevated (CKD indicator) |
|---|---|---|
| Canine | 0–14 µg/dL | > 14 µg/dL |
| Feline | 0–14 µg/dL | > 14 µg/dL |
SDMA elevation is considered an indicator of reduced renal function; values persistently > 14 µg/dL warrant further renal evaluation (IRIS staging).
4. Clinical Significance¶
- Early detection: SDMA rises when GFR drops to ~40% loss, earlier than creatinine (which rises at ~75% loss).
- IRIS staging: SDMA ≥ 18 µg/dL (canine) or ≥ 18 µg/dL (feline) contributes to IRIS CKD staging.
- Muscle-mass independence: reliable in cachectic/geriatric patients where creatinine underestimates disease.
5. SDMA vs Creatinine¶
| Attribute | SDMA | Creatinine |
|---|---|---|
| Affected by muscle mass | No | Yes |
| Early GFR loss detection | ~40% loss | ~75% loss |
| Affected by diet | No | Mildly |
| Pre-analytical stability | High | Moderate |
| IRIS staging utility | Yes | Yes |
6. Analytical Performance (Migibio Assay)¶
| Metric | Value |
|---|---|
| LOD | 0.5 µg/dL |
| LOQ | 1.0 µg/dL |
| Linear range | 1–100 µg/dL |
| Intra-assay CV% | < 8% |
| Inter-assay CV% | < 10% |
| Correlation vs reference (r) | > 0.95 |
7. Interpretation Guide¶
| SDMA (µg/dL) | Interpretation |
|---|---|
| 0–14 | Normal renal function |
| 14–18 | Borderline — recheck in 2–4 weeks |
| > 18 | Consistent with reduced GFR — pursue IRIS staging |
| > 25 | Advanced renal impairment — full workup |
8. FAQ¶
Q1. What is the difference between SDMA and creatinine?
SDMA is a methylated arginine derivative cleared almost exclusively by renal filtration and is not affected by muscle mass, so it rises when GFR drops to about 40% loss. Creatinine is affected by muscle mass and rises only at about 75% GFR loss. SDMA therefore detects kidney disease earlier and is more reliable in cachectic or geriatric patients.
Q2. When does SDMA become elevated?
SDMA rises when glomerular filtration rate (GFR) drops to roughly 40% loss — earlier than creatinine. Values persistently above 14 µg/dL warrant renal evaluation, and values at or above 18 µg/dL contribute to IRIS CKD staging.
Q3. What is the normal SDMA range for dogs and cats?
The reference range is 0–14 µg/dL for both dogs and cats. Values of 14–18 µg/dL are borderline and warrant rechecking in 2–4 weeks; values above 18 µg/dL are consistent with reduced GFR.
Q4. Does SDMA replace creatinine in kidney testing?
No. SDMA and creatinine are complementary. SDMA detects reduced GFR earlier and is independent of muscle mass; creatinine contributes to IRIS staging and routine monitoring. They are used together.
9. References¶
- Nabity MB, Lees GE, Boggess MM, et al. Symmetric dimethylarginine assay validation, stability, and evaluation as a marker for the early detection of chronic kidney disease in dogs. J Vet Intern Med. 2015;29(4):1036-1044. PMID: 26079532
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Authored by: Migibio Clinical & Scientific Affairs, Guangzhou Magic Biotech Co., Ltd.
Reviewed by: Migibio R&D Quality Committee
Last updated: 2026-08-13
Disclosure: Migibio (Guangzhou Magic Biotech Co., Ltd.) is the manufacturer of the FIA680/FIA880 analyzers and FICT reagents referenced in this content. See our Editorial & Review Policy.