High-Precision Procalcitonin Immunoassay for Sepsis Diagnosis & Antibiotic Stewardship
The PCT Antibody Pair enables quantitative measurement of Procalcitonin — the most specific biomarker for systemic bacterial infection and sepsis. PCT is released by extrathyroidal tissues in response to bacterial endotoxins and pro-inflammatory cytokines, rising within 2–4 hours of bacterial infection onset and peaking at 6–24 hours. Unlike CRP, PCT levels are not significantly elevated in viral infections, making it the preferred marker for antibiotic stewardship decision-making.
Validated across a linear range of 0.27–94.95 ng/mL with a clinical LoD of 0.02 ng/mL, within-run CV of ≤2.0%, and confirmed concordance with Roche PCT across 29 clinical samples, this antibody pair meets the precision and range requirements of critical care PCT monitoring.
Analytical performance verified across sensitivity, linearity, precision, stability, and inter-batch consistency.
Clinical LoD of 0.02 ng/mL and analytical LoD of 0.011 ng/mL. Accurately quantifies PCT at the 0.1 ng/mL low-risk sepsis threshold and the 0.5 ng/mL antibiotic guidance cut-off, where precision is most clinically critical.
Within-run CV of 2.0% at 2 ng/mL, 1.9% at 18 ng/mL, and 1.9% at 50 ng/mL (n=20 replicates per level) — substantially better than typical IVD precision specifications of ≤10%, ensuring reliable serial PCT trending.
Linear across 0.27–94.95 ng/mL — spanning low-risk (<0.5 ng/mL), moderate (0.5–2 ng/mL), high (2–10 ng/mL), and critical (>10 ng/mL) PCT zones in a single assay without dilution for most clinical presentations.
Accelerated stability testing at 37°C over 7 days shows signal deviation <10% — confirming reagent integrity during ambient shipping and supporting extended on-instrument stability for high-throughput analysers.
Three independent production batches tested across 6 calibrator levels show batch deviation <10% at all concentrations — confirming manufacturing reproducibility essential for IVD regulatory submission.
Method comparison across 29 clinical samples vs. Roche PCT reference demonstrates strong concordance, supporting clinical equivalence claims and facilitating regulatory documentation for IVD submissions.
All data generated using Sekbio anti-PCT monoclonal antibody pair in sandwich immunoassay format.
Six calibrators prepared by proportional dilution from high and low QC pools confirm linear dose-response across 0.27–94.95 ng/mL. Back-calculated concentrations are assessed against theoretical values across 3 test runs.
| Theoretical Value (ng/mL) | Run 1 (ng/mL) | Run 2 (ng/mL) | Run 3 (ng/mL) | Mean (ng/mL) |
|---|---|---|---|---|
| 94.95 | 111.61 | 100.99 | 98.22 | 103.61 |
| 76.23 | 76.74 | 78.43 | 78.84 | 78.00 |
| 57.24 | 55.73 | 54.82 | 54.92 | 55.16 |
| 38.25 | 33.51 | 34.24 | 34.70 | 34.15 |
| 19.26 | 15.48 | 15.57 | 15.55 | 15.54 |
| 0.27 | 0.27 | 0.27 | 0.26 | 0.27 |
| Linear range confirmed: 0.27–94.95 ng/mL. Three independent runs demonstrate consistent back-calculation across the full analytical range. | ||||
The analytical LoD is determined from the blank distribution (mean + 2 SD). The clinical LoD at 0.02 ng/mL achieves S/N ≥ 2.0, distinguishing it from blank at the 0.011 ng/mL analytical threshold.
| Concentration (ng/mL) | Run 1 (RLU) | Run 2 (RLU) | Run 3 (RLU) | Mean RLU | S/N |
|---|---|---|---|---|---|
| 0 (Blank) | 1,169 | 1,243 | 1,243 | 1,218 | 1.00 |
| 0.005 | 1,552 | 1,599 | 1,441 | 1,531 | 1.26 |
| 0.010 | 1,841 | 1,794 | 1,804 | 1,813 | 1.49 |
| 0.020 (Clinical LoD) | 2,392 | 2,679 | 2,397 | 2,489 | 2.04 |
| Clinical LoD = 0.02 ng/mL (S/N ≥ 2.0). Analytical LoD = 0.011 ng/mL (blank mean + 2 SD). Method: within-run precision, n=20 blank replicates. | |||||
Three QC levels measured in 20 replicate pairs demonstrate CV ≤2.0% — substantially below the IVD acceptance criterion of ≤10% and consistent with high-precision critical care analyzer performance.
| QC Level | Nominal Conc. (ng/mL) | Mean (ng/mL) | SD (ng/mL) | CV (%) |
|---|---|---|---|---|
| S1 (Low) | ~2 | 2.03 | 0.04 | 2.0% |
| S2 (Mid) | ~18 | 17.94 | 0.35 | 1.9% |
| S3 (High) | ~50 | 50.05 | 0.95 | 1.9% |
| n=20 replicates per level (2 lots × 10 replicates). Acceptance criterion: CV ≤ 10%. All levels meet criteria with substantial margin. | ||||
Three production batches tested against the same 6-level calibrator set show inter-batch deviation <10% across all concentration levels, confirming manufacturing consistency for IVD regulatory submissions.
| Theoretical (ng/mL) | Batch 1 Mean | Batch 2 Mean | Batch 2 Deviation | Batch 3 Mean | Batch 3 Deviation |
|---|---|---|---|---|---|
| 94.95 | 106.01 | 102.79 | −3.04% | 103.61 | −2.27% |
| 76.23 | 79.42 | 77.78 | −2.08% | 78.00 | −1.79% |
| 57.24 | 55.17 | 55.43 | +0.47% | 55.16 | −0.03% |
| 38.25 | 33.70 | 33.54 | −0.49% | 34.15 | +1.33% |
| 19.26 | 15.60 | 15.35 | −1.57% | 15.54 | −0.40% |
| 0.27 | 0.254 | 0.258 | +1.31% | 0.266 | +4.72% |
| All inter-batch deviations <10%. Acceptance criterion: <10% deviation vs. Batch 1 reference. | |||||
PCT antibody pair validated for sepsis diagnosis, antibiotic stewardship, and OEM immunoassay development.
PCT is the frontline biomarker for sepsis diagnosis in emergency and ICU settings. Levels >2 ng/mL indicate probable sepsis; >10 ng/mL indicate severe sepsis or septic shock. Wide linear range supports monitoring across all severity stages.
PCT-guided antibiotic protocols reduce unnecessary antibiotic use by 25–50% in respiratory tract infections and sepsis. The 0.02 ng/mL LoD enables accurate measurement at the 0.1–0.5 ng/mL low-risk thresholds where antibiotic withholding is indicated.
PCT declines by >50% per day in patients responding to antibiotics. CV ≤2.0% precision enables accurate serial trending, distinguishing treatment response from analytical noise at clinically relevant concentration changes.
Anti-PCT monoclonal antibody pair available as OEM raw material for CLIA analyzer manufacturers and FIA POCT kit developers. ISO 13485-compliant supply, batch consistency data available for regulatory submission support.
Request the full technical datasheet, antibody pair specifications, or discuss OEM supply and analyzer integration with our team.