Abstract: SA-PO0366
First Day of the Week vs. Midweek Dialysis Laboratory Assessment: Does Timing Matter?
Session Information
- Dialysis: Epidemiology and Facility Management
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Singh, Pratiksha, Samuel S Stratton Department of Veterans Affairs Medical Center, Albany, New York, United States
- Okoren, Nora, Samuel S Stratton Department of Veterans Affairs Medical Center, Albany, New York, United States
- Gosmanova, Elvira O., Samuel S Stratton Department of Veterans Affairs Medical Center, Albany, New York, United States
Background
Dialysis adequacy (urea reduction ratio-URR and Kt/V) and electrolyte parameters are regularly assessed in patients with ESKD on hemodialysis (HD). Traditionally, laboratory evaluation is performed during midweek (MW) dialysis; however, little is known about differences in URR, Kt/V, and electrolyte measurements performed during the first day of the week (FDW) versus MW dialysis sessions to support this practice.
Methods
This study was a quality improvement project including 36 adult patients with ESKD receiving HD triweekly at Stratton VAMC, Albany, NY. Fifty-three paired determinants of URR, Kt/V, serum potassium (Ks), sodium (Nas), bicarbonate (HCO3s), calcium (Cas), and phosphate (Ps) were compared between two consecutive FDW and MW dialysis sessions during a two-month period. URR > 65% and Kt/V > 1.2 were considered as adequate. Paired t-test was used to compare means of parameters of interest between FDW and MW dialysis.
Results
The discrepancy in dialysis adequacy between FDW and MW was observed in five instances, with three cases of suboptimal URR and Kt/V occurring at FDW but not at MW, and in two cases, the other way around. Shortened HD duration was the most common reason for not meeting URR/Kt/V. There were no differences between means of URR, Kt/V, Nas, and Cas measured at FDW versus MW (Table). Ps was 0.3 mg/dL higher before FDW than MW (p<0.005). Although more people had Ps > 5mg/dL before FWD (45%) than MW (40%) dialysis, the difference was not significant (p=0.35). The variations in Ks and HCO3s were statistically but not clinically significant (Table).
Conclusion
URR and Kt/V performed at FDW versus MW dialysis were similar. Dialysis adequacy determination performed during FDW does not overestimate URR/Kt/V. However, there were differences in levels of several electrolytes between FDW and MW. Ps was the most affected by day of the week when it was measured.
Laboratory parameters collected at first-day-of-the week versus mid-week dialysis sessions
| Parameter | FDW | MW | p-value |
| URR, mean (SD), % | 75.6 (6.5) | 75.0 (5.1) | 0.27 |
| Kt/V, mean (SD) | 1.6 (0.2) | 1.6 (0.2) | 0.32 |
| Serum Potassium, mean (SD), mEq/L | 4.7 (0.6) | 4.6 (0.6) | 0.005 |
| Serum Bicarbonate, mean (SD), mEq/L | 24.8 (2.6) | 26.2 (2.0) | <0.001 |
| Serum Phosphorus, mean (SD), mg/dL | 5.0 (1.6) | 4.7 (1.3) | 0.005 |
| Serum Calcium, mean (SD), mg/dL | 9.3 | 9.2 | 0.10 |
| Serum Sodium, mean (SD), mEq/L | 139 | 138 | 0.42 |
Funding
- Veterans Affairs Support