ATAGO MASTER-URC/Nα Urine Specific Gravity Refractometer

Overview

The ATAGO MASTER-URC/Nα is a precision handheld clinical refractometer engineered specifically for rapid, reliable measurement of urine specific gravity (USG) in point-of-care, veterinary, and laboratory settings. It operates on the principle of critical angle refractometry: incident light passes through a prism-sample interface, and the resulting refraction angle—governed by Snell’s law—is optically translated into a calibrated scale reading. The instrument features built-in automatic temperature compensation (ATC) across a clinically relevant range of 10–30°C, eliminating manual correction and ensuring consistent readings regardless of ambient fluctuations. Its optical path is optimized for aqueous biological fluids with low ionic variability, delivering high reproducibility in urinary matrix analysis without dilution or calibration drift. Designed for clinical rigor—not convenience—the MASTER-URC/Nα meets fundamental requirements for diagnostic support under ISO 15197:2013 (in vitro diagnostic devices) and aligns with CLIA-waived testing criteria when used per manufacturer instructions.

Key Features

• Optimized optical system with high-contrast, parallax-free scale view for unambiguous USG interpretation at 1.000–1.050 (0.001 resolution)
• Integrated automatic temperature compensation (ATC) using bimetallic thermal expansion elements—no electronics or batteries required
• IP65-rated housing (excluding eyepiece), providing full protection against dust ingress and resistance to water jets—validated per IEC 60529
• Chemically resistant polymer body engineered for repeated exposure to acidic and saline biological samples, including urine with elevated creatinine or protein content
• Minimal sample requirement: single 0.05 mL drop ensures rapid equilibration and eliminates cross-contamination risk between measurements
• Ergonomic, pocket-sized form factor (3.2 × 3.4 × 20.7 cm; 110 g) compatible with glove use and field deployment in mobile clinics or animal hospitals

Sample Compatibility & Compliance

The MASTER-URC/Nα is validated for undiluted human and veterinary urine specimens, including those exhibiting mild turbidity, moderate proteinuria (<30 mg/dL), or glucosuria (<100 mg/dL). It is not intended for use with highly viscous, lipid-rich, or hemolyzed samples, which may require centrifugation or alternative methodology per CLSI GP16-A3 guidelines. Device construction complies with RoHS Directive 2011/65/EU and REACH Annex XVII restrictions on hazardous substances. While not a Class II medical device under FDA 21 CFR Part 866, its performance characteristics meet ASTM D1218-22 (Standard Test Method for Refractive Index of Hydrocarbon Liquids) as adapted for aqueous physiological solutions. Calibration verification is performed using certified ATAGO standard solution (REF-1000) traceable to NIST SRM 1816.

Software & Data Management

As an analog optical instrument, the MASTER-URC/Nα does not incorporate digital data logging, Bluetooth, or software interfaces. All measurements are directly observable via the ocular scale and require manual transcription into electronic health records (EHR), laboratory information systems (LIS), or paper-based logs. This architecture eliminates cybersecurity vulnerabilities, firmware update dependencies, and battery-related failure modes—enhancing operational continuity in resource-constrained or offline environments. For auditability, users are advised to record measurement date/time, operator ID, and ambient temperature alongside each USG value in accordance with GLP documentation practices.

Applications

• Routine urinalysis in primary care clinics, emergency departments, and dialysis units to assess renal concentrating ability and hydration status
• Veterinary practice for evaluating dehydration, acute kidney injury, and post-anesthetic monitoring in dogs, cats, and equines
• Research laboratories conducting longitudinal studies on diuretic response, antidiuretic hormone (ADH) dynamics, or osmotic stress models
• Field deployment by public health teams during outbreak investigations requiring rapid triage of fluid balance disorders
• Quality control checks for urine collection protocols in biobanking and clinical trial specimen handling

FAQ

Does the MASTER-URC/Nα require calibration before each use?
No. It is factory-calibrated using distilled water (SG = 1.000) and requires only periodic verification—typically before first use of the day or after exposure to extreme temperatures—using ATAGO REF-1000 standard solution.
Can this refractometer measure serum or plasma osmolality?
No. It is optically and scale-calibrated exclusively for urine-specific gravity. Serum/plasma refractometry requires different prism geometry and scale mapping (e.g., ATAGO PAL-10S), as governed by differing solute composition and refractive index dispersion profiles.
What maintenance is required for long-term accuracy?
After each use, clean the prism surface with lens tissue and distilled water—never alcohol or abrasive cleaners. Store in the supplied protective case with desiccant to prevent moisture-induced haze. Replace the RE-2471-56M illumination plate every 24 months or if optical transmission degrades visibly.
Is the IP65 rating applicable during active measurement?
Yes. The sealed body maintains IP65 integrity during operation, though the eyepiece must remain uncovered for optical viewing. Do not submerge or expose the eyepiece to direct water spray.