Table 3. Assay Performance of CatB in Q-Buffer, Serum, or Plasmaa.
| A:Quantitation of CatB at Ultralow and Moderate Concentrations | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Two-Step Protocol |
Three-Step Protocol |
|||||||||
| Sample Type | Dilution | C Spike (pg/mL) | C Det. (pg/mL) Adjusted | SD (pg/mL) | Error (%) | Recovery (%) | C Det. (pg/mL) Adjusted | SD (pg/mL) | Error (%) | Recovery (%) |
| Q-buffer | D 0 | 1.20 | 0.00 | 0.00 | 100.00 | 0.00 | 0.00 | 0.00 | 100.00 | 0.00 |
| D 1 | 4.00 | 4.42 | 3.69 | 10.50 | 110.50 | 0.00 | 0.00 | 100.00 | 0.00 | |
| D 2 | 10.00 | 10.36 | 2.56 | 3.60 | 103.60 | 8.90 | 0.59 | 11.00 | 89.00 | |
| D 3 | 100.00 | 99.00 | 3.69 | 1.00 | 99.00 | 88.00 | 5.56 | 12.00 | 88.00 | |
| D 4 | 500.00 | 497.00 | 15.47 | 0.60 | 99.40 | 469.00 | 7.80 | 6.20 | 93.80 | |
| Serum | D 0 | 2.00 | 0.00 | 0.00 | 100.00 | 0.00 | 0.00 | 0.00 | 100.00 | 0.00 |
| D 1 | 6.00 | 4.00 | 8.37 | 33.33 | 66.67 | 1.00 | 0.74 | 83.33 | 16.67 | |
| D 2 | 20.00 | 22.00 | 2.46 | 10.00 | 110.00 | 16.00 | 0.56 | 20.00 | 80.00 | |
| D 3 | 100.00 | 113.00 | 3.30 | 13.00 | 113.00 | 90.00 | 11.02 | 10.00 | 90.00 | |
| D 4 | 500.00 | 534.00 | 11.19 | 6.80 | 106.80 | 468.00 | 9.43 | 6.40 | 93.60 | |
| Plasma | D 0 | 2.00 | 0.00 | 0.00 | 100.00 | 0.00 | 0.00 | 0.00 | 100.00 | 0.00 |
| D 1 | 6.00 | 1.00 | 0.00 | 83.33 | 16.67 | 2.00 | 0.64 | 66.67 | 33.33 | |
| D 2 | 20.00 | 21.00 | 7.58 | 5.00 | 105.00 | 17.00 | 0.45 | 15.00 | 85.00 | |
| D 3 | 100.00 | 105.00 | 11.83 | 5.00 | 105.00 | 90.00 | 0.55 | 10.00 | 90.00 | |
| D 4 | 500.00 | 515.00 | 16.75 | 3.00 | 103.00 | 462.00 | 22.58 | 7.60 | 92.40 | |
| B: Estimated Discriminant Values of CatB Concentrations in Serum and Plasma | ||||
|---|---|---|---|---|
| Two-Step Protocol |
Three-Step Protocol |
|||
| Serum | Plasma | Serum | Plasma | |
| LOD (pg/mL)b | 4.7 | 4.7 | 4.7 | 9.4 |
| LLOQ (pg/mL)b | 9.4 | 9.4 | 18.8 | 18.8 |
| Estimated Endogenous CatB (pg/mL, C spike = 0) | 176 | 125 | 80 | 48 |
| Estimated Discriminant Value (LLoQ/Endogenous, %) | 5.3% | 7.5% | 23.5% | 39.2% |
a
(A) Quantitation of CatB at ultralow and moderate concentrations—levels of catB were measured using a dilution series (D0–D4) within Q-Buffer as well as prediluted (1/256) serum and plasma. Expected (C Spike) and observed (C Det.) concentrations (pg/mL), standard deviation (SD), percent (%) error, and recovery are shown for two-step and three-step assay configurations. (B) Estimated Discriminant Values of CatB Concentrations. The estimated LoD, LLoQ, and endogenous levels of catB with the calculated discriminant value for catB (LLoQ/Endogenous, %) displayed for each of the two-step and three-step assay configurations.
b
Measurements based on ≥80% recovery.