Table 2: Concentrations and percent change in concentration of cefepime, meropenem and piperacillin over time in tubes containing EDTA and in Li-Hep with gel tubes.
Day 0 concentrations serve as reference concentrations for calculation of percent change. EDTA: ethylenediaminetetraacetic acid; Li-Hep: Lithium-heparin; CBC: complete blood count.
| EDTA tubes (whole blood used for CBC) Concentration (ug/mL) [% degradation] |
Li-Hep with gel Tubes (plasma used for metabolic panels) Concentration (ug/mL) [% degradation] |
|
|---|---|---|
| Cefepime | ||
| Patient 1 (dose 5.4 hours prior to blood draw) | ||
| Day 0 | 56.2 (0.0) | 64.7 (0.0) |
| Day 1 | 52.9 (5.9) | 61.0 (5.7) |
| Day 2 | 51.9 (7.7) | 56.9 (12.1) |
| Day 3 | 56.0 (0.4) | 54.9 (15.1) |
| Day 4 | 56.5 (−0.5) | 51.9 (19.8) |
| Day 5 | 53.9 (4.1) | 50.3 (22.3) |
| Day 6 | 50.3 (10.5) | 49.0 (24.3) |
| Patient 2 (dose 9.9 hours prior to blood draw) | ||
| Day 0 | 16.3 (0.0) | 12.3 (0.0) |
| Day 1 | 15.5 (4.9) | 12.6 (−2.4) |
| Day 2 | 14.7 (9.8) | 11.7 (4.9) |
| Day 3 | 14.2 (12.9) | 10.4 (15.4) |
| Day 4 | 16.5 (−1.2) | 9.5 (23.6) |
| Day 5 | 16.3 (0) | 9.3 (24.4) |
| Day 6 | 15.6 (4.3) | 9.8 (20.3) |
| Meropenem | ||
| Patient 1 (dose 6.1 hours prior to blood draw) | ||
| Day 0 | 1.2 (0.0) | 1.7 (0.0) |
| Day 1 | 1.4 (−16.7) | 1.8 (−5.9) |
| Day 2 | 1.4 (−16.7) | 1.9 (−11.8) |
| Day 3 | 1.5 (−25.0) | 1.8 (−5.9) |
| Day 4 | 1.3 (−8.3) | 1.7 (0) |
| Day 5 | 1.3 (−8.3) | 1.8 (−5.9) |
| Day 6 | 1.4 (−16.7) | 1.8 (−5.9) |
| Patient 2 (dose 6.4 hours prior to blood draw) | ||
| Day 0 | 1.0 (0.0) | 1.6 (0.0) |
| Day 1 | 1.1 (−10.0) | 1.7 (−6.2) |
| Day 2 | 1.0 (0.0) | 1.6 (0.0) |
| Day 3 | 1.1 (−10.0) | 1.5 (6.2) |
| Day 4 | 1.0 (0.0) | 1.7 (−6.2) |
| Day 5 | 1.1 (−10.0) | 1.7 (−6.2) |
| Day 6 | 1.0 (0.0) | 1.6 (0.0) |
| Piperacillin | ||
| Patient 1 (dose 3.6 hours prior to blood draw) | ||
| Day 0 | 13.5 (0.0) | 11.6 (0.0) |
| Day 1 | 12.8 (5.2) | 12.7 (−9.5) |
| Day 2 | 12.3 (8.9) | 11.8 (−1.7) |
| Day 3 | 12.1 (10.4) | 11.4 (1.7) |
| Day 4 | 12.3 (8.9) | 11.3 (2.6) |
| Day 5 | 11.8 (12.6) | 10.8 (6.9) |
| Day 6 | 11.6 (14.1) | 10.7 (7.8) |
| Patient 2 (dose 7.7 hours prior to blood draw) | ||
| Day 0 | 10.9 (0.0) | 12.4 (0.0) |
| Day 1 | 10.6 (2.8) | 11.7 (5.6) |
| Day 2 | 10.4 (4.6) | 11.5 (7.3) |
| Day 3 | 10.8 (0.9) | 12.2 (1.6) |
| Day 4 | 9.9 (9.2) | 11.0 (11.3) |
| Day 5 | 10.3 (5.5) | 11.6 (6.5) |
| Day 6 | 10.5 (3.7) | 10.6 (14.5) |