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Post-Filter Hematocrit

Validation of a Post-Filter Hematocrit Calculation Formula: A Comparative Analysis With Measured Post-Filter Hematocrit Values

Status
Recruiting
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07293936
Acronym
CRRTHCT
Enrollment
20
Registered
2025-12-19
Start date
2025-03-15
Completion date
2026-03-15
Last updated
2025-12-19

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Continuous Renal Replacement Therapy, Hemofilter Clotting, Renal Failure

Keywords

crrt, continuous renal replacement therapy, hemofilter clotting, post-filter hematocrit, filtration fraction

Brief summary

Filter clotting is a major complication of continuous renal replacement therapy (CRRT), resulting in blood loss, reduced treatment efficacy, and increased cost. One modifiable factor associated with filter clotting is filtration fraction (FF), or the proportion of plasma water being removed from the blood over the course of the filter. In convention, a cutoff of FF\<20-30% has been used to prevent hemofilter clotting, but no evidence correlating FF with hemofilter clotting has been documented. Some experts have proposed that post-filter hematocrit (Hct) could be a more direct marker for determining hemofilter clotting risk, but evidence supporting clinical utility of this marker is lacking. HCTpost=HCTpre/(FF(HCTpre-1)+1) In our proposed validation study, we hope to determine whether our formula for post-filter Hct provides accurate results when compared to measured values. The information obtained from this study will potentially justify the use of utilizing the formula in future studies. The procedure of this study is collecting blood samples from the post-filter lines of patients on CRRT at different time points and different flow rates. This will be considered the measured post-filter hematocrit which will then be compared to the calculated formula above, using the other values obtained from daily labs (for pre-filter hematocrit) and CRRT machine settings.

Detailed description

This investigational study is listed as other because it is a validation study comparing two measurement methods-comparing a calculated versus a machine-measured post-filter hematocrit- and is typically classified as a cross-sectional investigational study in the context of diagnostic or method comparison research.

Interventions

OTHERCalculated Post-Filter Hematocrit

using the formula: HCTpost=HCTpre/(FF(HCTpre-1)+1)

OTHERMeasured Post-Filter Hematocrit

Measured from blood sample taken from CRRT machine

Sponsors

Gwyndolyn M. Radford
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE

Intervention model description

All participants will undergo the same intervention of both using their blood samples to measure post-filter hematocrit and using their other lab values and CRRT settings to calculate post-filter hematocrit.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* patients initiated on CRRT age equal than or greater to 18 years of age

Exclusion criteria

* patients on ECMO

Design outcomes

Primary

MeasureTime frameDescription
Agreement between measured and calculated post-filter hematocrit values.Participation begins at consent and includes a single study procedure in which four post-filter blood samples are collected over ~40 minutes. Participation ends after the final draw. Generally, no longer than 1 day.Use Bland-Altman analysis to assess agreement and quantify bias and limits of agreement. Calculate correlation coefficients (Pearson or Spearman) to evaluate the strength of association.

Secondary

MeasureTime frameDescription
Analyze the impact of CRRT settings on discrepancies between measured and calculated Filtration FractionParticipation begins at consent and includes a single study procedure in which four post-filter blood samples are collected over ~40 minutes. Participation ends after the final draw. Generally, no longer than one day.How do different settings (e.g., Q\_B, Q\_UF, Q\_prefilter, Q\_postfilter) on the machine affect the discrepancies (if there are any) between calculated and measured filtration fraction. Will be using change in post-filter hematocrit values as the measured filtration fraction and comparing to calculated filtration fraction using standard flow-rate derived formula used in practice.
Subgroup analysis based on patient-specific factorsParticipation begins at consent and includes a single study procedure in which four post-filter blood samples are collected over ~40 minutes. Participation ends after the final draw.Post-filter hematocrit values will be stratified and compared across subgroups defined by baseline pre-filter hematocrit category, anticoagulation strategy (e.g., citrate vs. heparin vs. none), and blood-flow rate category. The metric reported will be the mean post-filter hematocrit within each subgroup and the between-group differences.

Countries

United States

Contacts

Primary ContactGwyndolyn M Radford, MD
gradford@uiowa.edu7858179620
Backup ContactBenjamin R Griffin, MD
benjamin-griffin@uiowa.edu5073631404

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026