Reasons for choosing our testing services
ZHONGXI Testing has obtained inspection qualification certifications from multiple countries and regions worldwide. We possess a senior testing team and advanced testing methods, providing independent, impartial, and professional third-party verification services for global carbon projects.
Internationally recognized authority
Certified by multiple international standards such as CNAS, VCS, and GS, with reports universally applicable worldwide.
Global service capability
Covering 140+ countries and regions, it supports on-site detection and remote verification in multiple languages.
Professional experimental methods
Adopt standard experimental methods to ensure accurate and reliable data.
A well-defined testing scope is the first sign of a competent laboratory. At our CNAS/CMA-accredited facility, we specialize in anti-nuclear antibody (ANA) testing, serving clients across pharmaceuticals, biotechnology, and research sectors. Our capabilities are aligned with global regulatory frameworks, ensuring reliability and reproducibility for critical analyses.
Testing Scope
Our ANA testing services cover a wide range of biological samples, including serum, plasma, and cell culture extracts. Applicable products span immunoassays, enzyme-linked immunosorbent assays (ELISAs), and Western blotting methods. Materials tested include human recombinant proteins, monoclonal antibodies, and polyclonal antisera. Grades of samples are categorized based on purity and concentration, with applications ranging from drug development to diagnostic validation. Commonly referenced standards include ASTM E1500, ISO 15189, EN 13968, and GB/T 18765, ensuring compliance with international best practices.
Testing Items and Parameters
Test items include qualitative and quantitative ANA detection, with parameters such as titer, specificity, and binding affinity. Typical test methods and graded limit requirements are outlined in the table below:
| Test Item | Typical Parameters | Graded Limit Requirements |
|---|---|---|
| Indirect Immunofluorescence (IIF) | Pattern recognition (homogeneous, speckled, nucleolar, etc.), titer range (1:40 to 1:640) | Reproducibility within ±15% for titer determination; pattern consistency verified by blind review |
| ELISA | Signal-to-baseline ratio, absorbance units (AU) | Detection limit ≤0.1 AU; coefficient of variation (CV) ≤10% for batch-to-batch analysis |
| Western Blot | Protein band specificity, intensity scoring (0-3+) | Identical band patterns for positive controls; CV ≤12% for reproducibility checks |
Additional parameters include incubation times, temperature control, and reference range alignment with clinical guidelines. All results are reported with pass/fail classifications based on predefined thresholds.
Data and Variation Analysis
Parallel-sample and batch-to-batch variation is rigorously assessed through statistical analysis. Relative deviation between parallel samples is calculated using the formula: [(Sample Value 2 - Sample Value 1) / Average Value] × 100%. Typical acceptance windows for ANA testing are within ±10% for quantitative parameters and ≤15% for qualitative pattern recognition. Batch-to-batch variation is monitored via internal standards, with relative standard deviation (RSD) maintained below 8% across all methods. Results are presented with confidence intervals (95%), and outliers are subjected to duplicate testing to validate consistency.
Process capability indices (Cp) and control charts are employed to ensure long-term stability. Deviations outside the 3σ limits trigger root cause investigations, with corrective actions documented per ISO 17025 requirements. All variation data is compiled in capability reports, including histograms, trend analyses, and acceptance criteria summaries.
Client-specific requirements are accommodated through customized testing protocols. Clients are welcome to share drawings, material grades or purchase specifications so that the testing plan can be matched precisely.