1. Analytical sensitivity (limit of detection)
For most routine lab assays:
- Immunoturbidimetric / Immunonephelometric methods:
≈ 2–5 mg/L (some high-sensitivity kits go slightly lower) - ELISA (research / specialized labs):
≈ 0.1–1 mg/L
Exact sensitivity always depends on the reagent kit and analyzer.
2. Clinical sensitivity (diagnostic usefulness)
α1-Microglobulin is highly sensitive for proximal tubular damage, especially:
- Early tubular proteinuria
- Drug-induced nephrotoxicity
- Diabetic nephropathy (tubular involvement)
- Heavy metal exposure (Cd, Pb)
It often rises earlier than serum creatinine, making it a sensitive early marker for tubular dysfunction.
3. Sample type matters
- Urine α1-microglobulin → highest diagnostic sensitivity
- Serum α1-microglobulin → more limited, mainly supportive