Assessment of comparison results of urine protein stability in two types of new Acti-Fine®
Vacuum containers with Boric Acid
and preservative stored at +20°C versus results from Acti-Fine® vacuum containers without additives stored at +4°C for 7 days.
and preservative stored at +20°C versus results from Acti-Fine® vacuum containers without additives stored at +4°C for 7 days.
The authors
Inna Shmidt 1, Ekaterina Atmadzheva 1, Svetlana Kovalevskaya 2
1. St. Luke Clinical Hospital, St. Petersburg, Russia
2. Pavlov State Medical University, St. Petersburg, Russia
1. St. Luke Clinical Hospital, St. Petersburg, Russia
2. Pavlov State Medical University, St. Petersburg, Russia
Clinical laboratories frequently need to validate new in vitro diagnostic devices, such as vacuum urine containers with different preservatives, to ensure analytical stability and result reliability. This study evaluates the stability of urine protein in new Acti-Fine® containers with boric acid and a preservative compared to standard additive-free containers.
To compare the stability of urine protein results in Acti-Fine® vacuum containers with boric acid and preservative (stored at +20°C) versus additive-free containers (stored at +4°C) over a 7-day period.
The study was conducted from June to August 2025 at St. Luke Clinical Hospital. Urine samples from 40 patients were collected in sterile containers and aliquoted into three types of 8.0 ml Acti-Fine® vacuum tubes:
• Type A: Without additives (reference, stored at +4°C)
• Type B: With boric acid (stored at +20°C)
• Type C: With preservative (chlorhexidine-based, stored at +20°C)
Protein concentrations were measured at 0, 24, 72, 120, and 168 hours using a Beckman Coulter AU480 analyzer. Protein was determined spectrophotometrically with pyrogallol red-molybdate reagent. Statistical analysis was
performed using MedCalc® V20.218.
• Type A: Without additives (reference, stored at +4°C)
• Type B: With boric acid (stored at +20°C)
• Type C: With preservative (chlorhexidine-based, stored at +20°C)
Protein concentrations were measured at 0, 24, 72, 120, and 168 hours using a Beckman Coulter AU480 analyzer. Protein was determined spectrophotometrically with pyrogallol red-molybdate reagent. Statistical analysis was
performed using MedCalc® V20.218.
Protein Stability (g/L):
• Type B (Boric Acid) minimal decrease, up to -3.6% at 168 hours.
• Type C (Preservative) slight increase, not exceeding +4.5% at all time points.
Stability was consistent across all protein concentration ranges (0–0.99 g/L, 1.00–1.99 g/L, 2.00–2.99 g/L, ≥3.00 g/L), with no significant deviations (p > 0.05).
The Passing-Bablok regression method showed no significant differences between results from VCT type A (no additives) and VCT type B/C.
• Type B (Boric Acid) minimal decrease, up to -3.6% at 168 hours.
• Type C (Preservative) slight increase, not exceeding +4.5% at all time points.
Stability was consistent across all protein concentration ranges (0–0.99 g/L, 1.00–1.99 g/L, 2.00–2.99 g/L, ≥3.00 g/L), with no significant deviations (p > 0.05).
The Passing-Bablok regression method showed no significant differences between results from VCT type A (no additives) and VCT type B/C.
1.Urine protein results from Acti-Fine® tubes with boric acid or preservative stored at +20°C show excellent correlation (r > 0.999) with results from additive-free tubes stored at +4°C.
2. Both types of test tubes provide reliable stability for urine protein for at least 7 days, with preservative tubes showing slightly better performance (+3.6% maximum change vs -3.6% for boric acid tubes).
3. The observed changes are not clinically significant, making both container types suitable for routine clinical use.
2. Both types of test tubes provide reliable stability for urine protein for at least 7 days, with preservative tubes showing slightly better performance (+3.6% maximum change vs -3.6% for boric acid tubes).
3. The observed changes are not clinically significant, making both container types suitable for routine clinical use.
