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Analytical and diagnostic evaluation of the Anvajo fluidlab 2 analyzer: a novel urine particle analyzer for clinical application using digital holographic microscopy?

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Published/Copyright: January 2, 2026
Clinical Chemistry and Laboratory Medicine (CCLM)
From the journal Clinical Chemistry and Laboratory Medicine (CCLM) Volume 64 Issue 5

Abstract

Objectives

The performance of a novel urine particle analyzer, fluidlab 2 (Anvajo GmbH, Dresden, Germany), was evaluated against phase-contrast visual microscopy according to the most recent EFLM European Urinalysis Guideline.

Methods

The fluidlab 2 device combines digital holographic microscopy with neural network-based object detection for particle classification. Its compact benchtop design is suitable for bedside use, reducing turnaround times. The analytical performance (imprecision, linearity, LoQ) was evaluated according to the 2023 EFLM Urinalysis Guideline. Method comparison involved the analysis of 450 urine samples, assessing RBC, WBC, and SEC counts against visual microscopy using Passing-Bablok regression and Spearman’s correlation. Bland-Altman plots were used to evaluate the agreement with clinical performance standards, while weighted Cohen’s kappa was used to measure diagnostic agreement on an ordinal scale.

Results

By applying Dahlberg’s procedure, a desirable relative coefficient of variation R(CV) ≤2.0 was obtained for RBC and WBC. Linearity of up to 7 × 106/L and 6 × 106/L was achieved. The estimated LoQ at CV=30 % reached 20 × 106/L for RBC and 5 × 106/L for WBC. Spearman’s correlation coefficient against visual microscopy was 0.86, 0.92 and 0.94 for RBC, WBC and SEC, respectively. Agreement with visual microscopy (Cohen’s weighted kappa) was 0.92 for RBC, 0.93 for WBC, 0.96 for SEC, 0.86 for casts, 0.82 for non-SEC, 0.33 for crystals and 0.51 for bacterial counts.

Conclusions

Fluidlab 2 provides desirable imprecision for RBC and WBC, and meets the criteria for linearity and LoQ. Cohen’s weighted kappa coefficients show an optimal comparison to visual microscopy for RBC, WBC and SEC and a minimum comparison for casts and non-SEC. This evaluation demonstrated promising results for the use of the fluidlab 2 analyzer in a clinical setting to detect kidney-related diseases based on urine particle analysis.

Keywords: urinalysis; urine particle analysis; hematuria; point-of-care testing
Corresponding author: Matthijs Oyaert, Pharm, PhD, Department of Laboratory Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium, E-mail:

Acknowledgments

The authors wish to thank the lab technicians of the Ghent University Hospital for their assistance in the study. We thank ANVAJO for providing the reagents for this evaluation.

  1. Research ethics: The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013) and approved by the Ethical Committee of the Ghent University Hospital (ONZ-2024-0086).

  2. Informed consent: Not applicable.

  3. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: None declared.

  5. Conflict of interest: The authors state no conflict of interest.

  6. Research funding: None declared.

  7. Data availability: The data that support the findings of this study are available from the corresponding author, MO, upon reasonable request.

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Supplementary Material

This article contains supplementary material (https://doi.org/10.1515/cclm-2025-1202).

Received: 2025-09-12
Accepted: 2025-12-11
Published Online: 2026-01-02
Published in Print: 2026-04-24

© 2025 Walter de Gruyter GmbH, Berlin/Boston

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https://doi.org/10.1515/cclm-2025-1202
Keywords for this article
urinalysis; urine particle analysis; hematuria; point-of-care testing

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Optimising lipoprotein(a) tests: we are almost there
  4. Review
  5. Blood biomarkers in neurodegenerative diseases: pre-analytical, analytical, and post-analytical challenges
  6. Opinion Papers
  7. From automation to agentic artificial intelligence in laboratory medicine: an opinion of the IFCC Division on Emerging Technologies
  8. From conventional to personalized reference intervals and decision limits: addressing latent errors in the post-post analytical phase
  9. The democratization of cancer screening, or a waste of valuable resources?
  10. Candidate Reference Measurement Procedures and Materials
  11. Development and validation of a candidate reference measurement procedure for free triiodothyronine and free thyroxine in human serum using equilibrium dialysis isotope-dilution liquid chromatography-tandem mass spectrometry
  12. General Clinical Chemistry and Laboratory Medicine
  13. From ordering to interpretation: a comprehensive framework for laboratory test indications
  14. Green laboratory through test ordering appropriateness and innovation
  15. From venipuncture to self-sampling dried blood spots: a shift in monitoring testosterone levels
  16. Serum GFAP as a biomarker for progression in multiple sclerosis: assay comparison and a large reference database of healthy controls
  17. Serial measurements of neuron specific enolase, glial fibrillary acidic protein and neurofilament light for mortality prediction in patients with severe acute brain injury in the ICU
  18. On the cusp of global lipoprotein(a) standardization
  19. Quantitative analysis of phylloquinone (vitamin K1) and menaquinone (vitamin K2) in serum of Russians by liquid chromatography-tandem mass spectrometry
  20. Analytical and diagnostic evaluation of the Anvajo fluidlab 2 analyzer: a novel urine particle analyzer for clinical application using digital holographic microscopy?
  21. Kappa Index predicts disease activity and transition to high-efficacy therapies in multiple sclerosis
  22. Laboratory solution to diagnose and monitor atypical IgG4-mediated anti-GBM disease
  23. Reference Values and Biological Variations
  24. Personalized reference intervals based on biological variation for serum bone turnover markers in healthy older adults
  25. Optimizing diagnostic thresholds of total vitamin B12 (B12) for identifying cobalamin deficiency in adults with macrocytic anemia
  26. Biological variation and inter-relation between key calcium homeostasis biomarkers
  27. Hematology and Coagulation
  28. Antiphosphatidylserine/prothrombin antibodies define a high-risk antiphospholipid syndrome profile associated with organ damage
  29. Cardiovascular Diseases
  30. Evaluation of the MAGLUMI non-competitive angiotensin I chemiluminescence immunoassay for measuring renin activity in human plasma
  31. Cardiac troponin T measurement following cardiac surgery in children with congenital heart defects predicts adverse outcomes
  32. Measurement of lipoprotein(a) via a novel point of care approach with comparison to established laboratory assays
  33. Letters to the Editor
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