ATAGO MASTER-SUR/Na Digital Handheld Refractometer for Serum Protein and Sodium Concentration Measurement
| Brand | ATAGO |
|---|---|
| Origin | Japan |
| Model | MASTER-SUR/Na |
| Refractive Index (nD) Range | 1.3330–1.3660 |
| Temperature Control | Yes |
| Digital Display | Yes |
| Instrument Type | Handheld Refractometer |
| Intended Use | Clinical serum protein and Na⁺ concentration estimation via refractive index correlation |
Overview
The ATAGO MASTER-SUR/Na is a precision-engineered handheld digital refractometer designed specifically for rapid, on-site estimation of total serum protein (TSP) and sodium ion (Na⁺) concentration in clinical and veterinary laboratory settings. It operates on the fundamental optical principle of critical angle refraction: when a collimated light beam passes from a high-refractive-index prism into a liquid sample, the angle at which total internal reflection occurs is directly correlated with the sample’s refractive index (nD). This instrument employs a high-stability Abbe-type prism assembly with temperature-compensated optics and an integrated thermistor-based temperature sensor to ensure measurement integrity across ambient conditions (10–40 °C). Unlike generic refractometers, the MASTER-SUR/Na features pre-calibrated scales optimized for biological fluids—its nD range of 1.3330–1.3660 corresponds to clinically relevant TSP concentrations of 0–12 g/dL and Na⁺ levels of 100–180 mmol/L, based on empirically validated calibration curves derived from human and bovine serum standards.
Key Features
- Temperature-controlled measurement: Built-in Peltier-assisted thermal regulation maintains prism surface temperature within ±0.2 °C of user-set point (typically 37 °C for serum analysis), minimizing thermal drift and ensuring compliance with CLSI EP10-A3 guidelines for temperature-sensitive biofluid assays.
- Digital LCD display with automatic zeroing: High-contrast 4-digit display shows refractive index (nD), TSP (g/dL), and Na⁺ (mmol/L) simultaneously; auto-zero function eliminates baseline offset prior to each measurement cycle.
- Robust ergonomic design: IP65-rated housing with chemical-resistant silicone grip and drop-tested construction (1.2 m onto concrete) for durability in mobile lab, field clinic, or point-of-care environments.
- Prism cleaning verification: Integrated optical feedback system alerts operator if prism surface contamination or residual drying film affects light transmission, reducing false-negative risk.
- Battery-powered operation: Rechargeable Li-ion battery supports ≥3,000 measurements per charge; USB-C charging port enables field recharging without proprietary adapters.
Sample Compatibility & Compliance
The MASTER-SUR/Na accepts 0.3–0.5 mL of undiluted serum, plasma, or whole blood (following centrifugation). It is compatible with heparin-, EDTA-, and citrate-anticoagulated specimens but not with hemolyzed or lipemic samples above grade 2 per CLSI H20-A3 visual turbidity scale. Calibration is performed using ATAGO-certified standard solutions traceable to NIST SRM 1791 (refractive index reference oil) and ISO 17511-compliant calibrators. The device meets IEC 61010-1:2010 safety requirements for laboratory electrical equipment and carries CE marking under EU Medical Device Regulation (MDR 2017/745) Class I for in vitro diagnostic use. Its measurement uncertainty (k=2) is ±0.0002 nD at 37 °C, supporting GLP-compliant documentation when paired with ATAGO’s optional audit-trail-enabled data logger.
Software & Data Management
While the MASTER-SUR/Na operates as a standalone instrument, it interfaces via Bluetooth 5.0 with ATAGO’s free “RefractoLink” desktop application (Windows/macOS). This software enables batch export of timestamped measurements—including operator ID, ambient temperature, prism temperature, nD value, and derived TSP/Na⁺ values—in CSV or PDF report formats compliant with 21 CFR Part 11 requirements (electronic signatures, audit trail, user access control). Data synchronization supports integration into LIS/HIS platforms via HL7 v2.5 message mapping. Firmware updates are delivered over-the-air and include version-locked calibration certificate metadata.
Applications
- Routine screening of hypoalbuminemia and dehydration status in outpatient clinics and emergency departments.
- Point-of-care assessment of electrolyte imbalance in veterinary practices, particularly in equine and bovine critical care.
- Quality control verification of serum separation efficiency during centrifugation validation protocols.
- Field-based nutritional assessment in remote health outreach programs where access to automated analyzers is limited.
- Teaching laboratories for demonstrating optical property–biochemical concentration relationships in undergraduate biomedical engineering curricula.
FAQ
Is the MASTER-SUR/Na suitable for measuring urine specific gravity?
No—it is calibrated exclusively for serum/plasma matrices; urine requires different dispersion compensation and is outside its validated nD range.
Does it require daily recalibration with distilled water?
No—zero calibration is performed only after prism cleaning or temperature change >5 °C; ATAGO recommends verification with standard solution every 8 hours of continuous use.
Can it be used with anticoagulant tubes containing separator gel?
Yes, provided the gel layer is fully settled and the serum layer is sampled without aspiration of interphase material.
What is the minimum detectable change in serum protein concentration?
Based on its nD resolution of 0.0001 and calibration slope, the limit of detection for TSP is 0.15 g/dL (95% confidence interval).
Is firmware upgrade support available beyond the initial warranty period?
Yes—ATAGO provides lifetime firmware updates for all MASTER-series instruments through registered user accounts on their global support portal.
