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Abstract: TH-PO668

Variation of Hemoglobin and Hematocrit by Timing of Blood Sampling in Hemodialysis Patients

Session Information

  • Anemia and Iron Metabolism
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Anemia and Iron Metabolism

  • 200 Anemia and Iron Metabolism


  • Tantiyavarong, Pichaya, Thammasat University Faculty of Medicine, Khlong Nueng, Pathum Thani, Thailand
  • Weeravittayasate, Jakkrathip, Thammasat University Faculty of Medicine, Khlong Nueng, Pathum Thani, Thailand

Hemoglobin (Hb) and hematocrit (Hct) have been used to monitor anemia treatment and their values depending on plasma volume. In long hemodialysis interval, patients usually incur higher weight gain, which may lower Hb and Hct levels. This study aimed to compare Hb and Hct regarding blood sampling times.


The prospective observational study was conducted in 103 patients receiving three hemodialysis sessions per week. Hb, automated and centrifuged Hct were collected pre- and post-dialysis in three consecutive sessions. Primary outcome was to compare these measures between blood sampling periods (one long and two short intervals). Secondary outcomes were correlation with body weight loss, correlation between Hb and Hct, and agreement of automated and centrifuged Hct.


There was no difference in the mean pre-dialysis Hb (10.1 ± 1.2 vs 10.3 ± 1.3 vs 10.3 ± 1.3 g/dL in long and two short intervals respectively; p = 0.320), automated Hct (31.0 ± 4.0 vs 31.7 ± 4.4 vs 31.8 ± 4.2%; p = 0.372) and centrifuged Hct (34.0 ± 4.6 vs 35.8 ± 6.1 vs 35.2 ± 4.8%; p = 0.054). Weight losses were correlated with all incremental measures. Hb were strongly correlated with automated Hct (r = 0.98, p < 0.001) and centrifuged Hct (r = 0.86, p < 0.001). Centrifuged Hct was higher than automated Hct (mean difference of 3.65%).


Timing of pre-dialysis blood samplings did not impact the level of Hb, automated or centrifuged Hct. Either Hb or Hct can be used to monitor renal anemia.

Effects of hydration status on hemoglobin, automated and centrifuged hematocrit: A – C) Comparison between pre and post-dialysis among three dialysis sessions; D – F) Incremental changes and body weight losses.
Abbreviation: HD-1, the first hemodialysis session (long interval); HD-2, the second hemodialysis session (short interval); HD-3, the third hemodialysis session (short interval).