Human Plasma,
Rheumatoid Factor (RF) Positive
Disease-state human plasma from donors with confirmed elevated rheumatoid factor levels. Available across six titer thresholds — from >200 to >4,000 IU/mL — for immunoassay development, QC panels, and IVD reagent manufacturing.
Six Titer Levels
>200, >500, >700, >1,000, >2,500, >4,000 IU/mL — matched to your assay range.
Confirmed RF Positivity
Each lot is screened and released against the stated titer threshold with full donor documentation.
IVDR-Ready Matrix
Human plasma matrix for IVDR Class B/C performance validation and positive control formulation.
EU Stock & Lot Reservation
Supplied from Europe via SeamlessBio. Lot reservation available for long-term manufacturing projects.
Available Titer Levels
All six variants are produced to the same quality standard — choose the threshold that fits your assay window.
| RF Titer | Typical Application | Format |
|---|---|---|
| > 200 IU/mL | Low-range screening, threshold controls | 1 – 50 mL |
| > 500 IU/mL | Standard positive control, ELISA validation | 1 – 50 mL |
| > 700 IU/mL | Mid-range; matrix and interference studies | 1 – 50 mL |
| > 1,000 IU/mL | High-titer positive control, QC panel anchoring | 1 – 50 mL |
| > 2,500 IU/mL | Elevated-range stress testing and linearity | 1 – 50 mL |
| > 4,000 IU/mL | Hook-effect studies, maximum-range calibration | 1 – 50 mL |
Product Specifications
Full lot documentation including CoA and donor screening data is supplied with every order.
Applications
RF-positive plasma is required wherever a human-matrix positive control with defined autoantibody titer is needed.
- Immunoassay development for RF detection (ELISA, CLIA, nephelometry, latex agglutination)
- Positive control material for IVD kit QC panels
- Cross-reactivity and specificity studies in autoimmune assay development
- Linearity and hook-effect evaluation at high titer levels
- IVDR analytical performance assessment — sensitivity and specificity
- Calibrator matrix formulation for quantitative RF assays
- Proficiency testing and external QC programs for clinical labs
- Research into complement activation and RF-mediated immune complex formation
Frequently Asked Questions
Common questions from assay developers and IVD manufacturers.
What is RF-positive human plasma used for in diagnostics?
RF-positive plasma serves as a disease-state positive control in immunoassays that detect rheumatoid factor (RF) — an autoantibody elevated in rheumatoid arthritis and other autoimmune conditions. It is used for assay development, calibration, QC panel formulation, and IVDR performance validation of RF detection kits (ELISA, CLIA, nephelometry, latex agglutination).
What is the difference between the six titer levels?
Each titer level defines the minimum confirmed RF concentration in the plasma: >200, >500, >700, >1,000, >2,500, and >4,000 IU/mL. Lower titers are used for threshold controls and screening assays; higher titers are needed for linearity studies, hook-effect testing, and high-range calibration. Choose the level that matches your assay's measurement range.
Is this plasma suitable for IVDR compliance?
Yes. The human plasma matrix and confirmed RF titer make this material suitable for IVDR analytical performance studies including sensitivity, specificity, and trueness assessment for Class B and C in-vitro diagnostic devices. Full lot documentation (CoA, donor screening data) is supplied with every order to support your technical file.
Can I order multiple titer levels in one shipment?
Yes — mixed-titer orders are welcome. If your QC panel requires several levels, we can consolidate all variants into a single shipment with matched lot documentation. Contact us with your requirements and we will provide a combined quote.
What volumes are available?
Standard volumes are 1, 2, 5, 10, 20, and 50 mL per titer level. For larger bulk quantities (>50 mL), please contact us to discuss lot availability and lead time.
How should RF-positive plasma be stored?
Store at −20 °C upon receipt. Avoid repeated freeze-thaw cycles, as these can degrade antibody activity and affect titer accuracy. For frequent use, aliquot into single-use volumes before freezing.
What is the typical lead time?
Lead time is typically 2–4 weeks depending on lot availability. For long-term manufacturing projects, lot reservation is available — contact us early to secure a dedicated lot for your production schedule.
Is this product available for research use only (RUO)?
Yes. This material is available for both RUO (Research Use Only) and IVD manufacturing use. It is not intended for direct clinical diagnostic use on patient samples.
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