ATAGO PEN-URINE S.G. Digital Pocket Refractometer for Urine Specific Gravity

Overview

The ATAGO PEN-URINE S.G. Digital Pocket Refractometer is a precision optical instrument engineered for rapid, field-ready measurement of urine specific gravity (USG) in clinical, veterinary, and point-of-care settings. It operates on the principle of total internal reflection at the prism-sample interface, where the critical angle of refraction correlates directly with the solute concentration—and thus the specific gravity—of aqueous urine samples. Built around a high-stability sapphire-coated prism and temperature-compensated optical path, the device delivers consistent readings across ambient conditions ranging from 10 °C to 40 °C without manual calibration adjustment. Its compact, pen-style ergonomics enable one-handed operation, making it suitable for high-throughput urinalysis workflows in emergency departments, mobile clinics, and animal health practices. Unlike analog refractometers, the PEN-URINE S.G. integrates real-time digital signal processing to eliminate parallax error and operator interpretation bias.

Key Features

• High-resolution digital LCD display showing specific gravity values to four decimal places (e.g., 1.0245)
• Automatic temperature compensation (ATC) based on built-in thermistor, referenced to 20 °C per ISO 21748
• Sapphire-coated measuring prism for enhanced scratch resistance and long-term optical stability
• Single-drop sample requirement (0.3 mL), minimizing waste and enabling serial testing with minimal reagent consumption
• Battery-powered operation (2 × AAA batteries, ~10,000 measurements per set) with auto-power-off after 3 minutes of inactivity
• IP65-rated housing for dust and water resistance—suitable for use in humid or splash-prone environments
• No external calibration required during routine use; factory-calibrated using NIST-traceable sodium chloride standards

Sample Compatibility & Compliance

The PEN-URINE S.G. is validated for use with human and animal urine specimens, including those containing moderate levels of glucose, protein, or ketones—common interferents in clinical urinalysis. It does not require dilution or pretreatment of fresh, uncentrifuged urine. The instrument conforms to international metrological standards for refractometric measurement: JIS K 0061 (Japanese Industrial Standard for refractometers), ISO 21748 (Guidance for the evaluation of measurement uncertainty in refractometry), and ASTM D1218 (Standard Test Method for Refractive Index of Hydrocarbon Liquids). While not a Class II medical device under FDA 21 CFR Part 860, its performance characteristics align with CLIA-waived testing requirements when used per manufacturer instructions. Data output is non-electronic; therefore, no 21 CFR Part 11 compliance is applicable—but documentation of instrument ID, calibration date, and operator signature satisfies GLP/GMP traceability needs in regulated laboratories.

Software & Data Management

The ATAGO PEN-URINE S.G. functions as a standalone optical measurement tool and does not incorporate Bluetooth, USB, or data logging capabilities. All measurements are displayed locally and must be manually recorded. This design prioritizes reliability, battery longevity, and regulatory simplicity—particularly advantageous in environments where electromagnetic interference, cybersecurity protocols, or audit trail validation would complicate connected instrumentation. For facilities requiring electronic recordkeeping, integration is achieved via manual entry into LIS (Laboratory Information Systems) or EMR platforms using standardized USG result fields. ATAGO provides optional calibration verification kits (Model: REF-URINE) with certified reference solutions traceable to NIST SRM 1890b, supporting periodic performance checks aligned with CAP and COLA accreditation checklists.

Applications

• Routine assessment of renal concentrating ability in outpatient and inpatient nephrology evaluations
• Dehydration screening in pediatric, geriatric, and athletic populations
• Monitoring diuretic therapy efficacy and fluid balance in critical care units
• Veterinary diagnostics—including canine, feline, and equine urinalysis for chronic kidney disease staging
• Quality control of urine collection and transport conditions in multicenter clinical trials
• Educational use in medical, nursing, and veterinary technician training programs

FAQ

What is the recommended calibration frequency for clinical use?
Calibration verification using ATAGO’s REF-URINE standard solution is advised before each shift or after every 20 patient samples—whichever occurs first—to ensure continued accuracy within ±0.0010.
Can this refractometer measure other bodily fluids such as serum or CSF?
No. The optical algorithm and temperature compensation curve are specifically optimized for urine-specific ionic composition and density range (1.0000–1.0600); use with other matrices may yield non-linear or biased results.
Is cleaning the prism required between samples?
Yes. A single-use lint-free tissue or soft optical wipe moistened with distilled water must be used to remove residual urine film prior to next measurement—alcohol-based cleaners are prohibited due to potential prism coating degradation.
Does the device meet ISO 13485 requirements?
While ATAGO’s manufacturing facility is ISO 13485-certified, the PEN-URINE S.G. itself is classified as a general-purpose laboratory instrument—not a medical device—under current EU MDR and FDA definitions, and thus carries no device-specific CE marking or 510(k) clearance.