Early vs. Late Tourniquet Release and Phlebotomy-Induced Hemolysis in the Emergency Department: TOURNI-ED

NCT07617103 | Completed

• 1 other identifier: 09.2026.829
• Study Type: interventional
• Target: 792
• Locations: 1 country
• Sites: 1

Brief Summary

BACKGROUND: Hemolysis is the most common preanalytical error in emergency department (ED) laboratories, affecting 12-26% of blood samples collected in the ED and leading to test cancellations, repeat venipuncture, delayed diagnoses, and increased healthcare costs. Venous stasis created by tourniquet application during phlebotomy is a recognized contributing factor to hemolysis. While clinical guidelines recommend releasing the tourniquet once blood flow is established, the optimal timing of tourniquet release in relation to tube filling sequence has not been systematically evaluated. OBJECTIVE: The primary objective of this trial is to determine whether early release of sphygmomanometer-applied venous stasis (released after the first tube fills) reduces hemolysis rates compared to late release (released after the last tube fills) during routine phlebotomy in ED patients triaged as green or yellow category. DESIGN: Single-center, parallel-group, superiority randomized controlled trial with 1:1 allocation ratio. The trial was prospectively registered prior to the enrollment of the first participant. PARTICIPANTS: Adult patients (≥18 years) presenting to the emergency department with triage category green (semi-urgent) or yellow (urgent), for whom blood collection is indicated as part of routine clinical care. At least two collection tubes had to be ordered, because the intervention is defined by the timing of cuff release relative to tube filling. Patients requiring blood collection from an intravenous catheter, those with known coagulation disorders, and those who decline to participate are excluded. INTERVENTIONS: Group A (Early Release): Sphygmomanometer inflated to 60 mmHg for venous stasis; tourniquet released as soon as blood flow into the first tube (sodium citrate, blue cap) is observed. All remaining tubes are collected after release. Group B (Late Release): Sphygmomanometer inflated to 60 mmHg; tourniquet maintained throughout all tube filling and released only after the last collection tube completes filling. Tube collection order follows the CLSI H03-A6 standard for both groups. PRIMARY OUTCOME: Hemolysis rate, defined as the proportion of serum separator tube (SST/yellow cap) samples with a Hemolysis Index (HI) ≥ 1+ (corresponding to free hemoglobin ≥50 mg/dL), is assessed by the clinical chemistry laboratory analyzer. The outcome assessor (laboratory technician) is blinded to group assignment. SECONDARY OUTCOMES: (1) Distribution of ordinal hemolysis index categories (-, 1+, 2+, 3+, 4+, 5+) in SST samples; (2) Proportion of hemolyzed samples requiring repeat blood collection; (3) Duration of venous stasis (seconds), from sphygmomanometer inflation to deflation of the cuff; (4) Complication rate (hematoma or ecchymosis, local swelling, oozing at the puncture site, vasovagal reaction, nerve injury, arterial puncture, or more than two venipuncture attempts). SAMPLE SIZE: Assuming hemolysis rates of 12% with late release and 6% with early release, a 2-sided alpha of 0.05, 80% power, and the normal approximation for two proportions with pooled variance, 356 participants per group were required. Allowing approximately 10% attrition, the enrollment target was 396 per group (792 total), and this was reached. RANDOMIZATION: A restricted allocation sequence of 792 assignments in a 1:1 ratio, without stratification, was generated with Research Randomizer (randomizer.org) before the start of enrollment. The sequence as implemented is not consistent with any single fixed block size, so no block size is claimed. The complete sequence was fixed before the first participant was enrolled, was embedded in the electronic data collection application, and was not accessible to the enrolling nurse; a participant's allocation was released only after eligibility had been confirmed and the participant had been enrolled. The realized allocation was 396 participants per group. STATISTICAL ANALYSIS: Primary analysis: intention-to-treat, comparing hemolysis rates with the Pearson chi-square test with Yates continuity correction; the composite complication outcome was compared with the Pearson chi-square test without continuity correction. Secondary analyses: Mann-Whitney U test for the ordinal hemolysis index distribution and for continuous outcomes; logistic regression for the adjusted odds ratio. A Bonferroni-adjusted alpha of 0.0125 was applied across the four confirmatory secondary endpoints; exploratory analyses used alpha of 0.05. Per-protocol analysis was performed as a sensitivity analysis. Missing primary outcome data were addressed with four prespecified scenarios (complete case, best case, worst case, and a tipping-point analysis); the complete-case analysis is reported as primary.

Conditions

Hemolysis; Blood Specimen Collection; Phlebotomy; Venous Stasis

Keywords

hemolysis; phlebotomy; tourniquet; venous stasis; emergency department; blood collection; hemolysis index; randomized controlled trial

Outcome Measures

Primary Outcomes (1)

• Hemolysis Rate (Proportion of Hemolyzed Serum Separator Tube Specimens)

  The proportion of serum separator tube (SST/yellow cap) specimens with a Hemolysis Index (HI) of ≥1+ (corresponding to free hemoglobin concentration ≥50 mg/dL), as measured by the clinical chemistry laboratory analyzer. The HI is reported on a six-category ordinal scale: (-) \<50 mg/dL; (1+) 50-99 mg/dL; (2+) 100-199 mg/dL; (3+) 200-299 mg/dL; (4+) 300-500 mg/dL; (5+) \>500 mg/dL. A specimen is classified as hemolyzed if HI ≥1+.

  Measured at the time of laboratory analysis, within 2 hours of blood collection

Secondary Outcomes (4)

• Ordinal Distribution of Hemolysis Index Categories

  Measured at the time of laboratory analysis, within 2 hours of blood collection

• Proportion of Specimens Requiring Repeat Blood Collection Due to Hemolysis

  Within the same emergency department visit (up to 24 hours post-collection)

• Duration of Venous Stasis

  Measured during the blood collection procedure

• Procedural Complication Rate

  During the blood collection procedure and up to 30 minutes post-procedure

Study Arms (2)

Early Release Group (Group A)

EXPERIMENTAL

Venous stasis is applied using a sphygmomanometer inflated to 60 mmHg. The sphygmomanometer is released (deflated to 0 mmHg) as soon as blood flow into the first blood collection tube (sodium citrate, 2.7 mL, blue cap) is observed. All remaining tubes are collected without active venous stasis. The tube collection order follows the CLSI H03-A6 guidelines for all participants.

Procedure: Sphygmomanometer-Applied Venous Stasis with Varied Release Timing During Phlebotomy

Late Release Group (Group B)

ACTIVE COMPARATOR

Venous stasis is applied using a sphygmomanometer inflated to 60 mmHg. The sphygmomanometer is maintained at 60 mmHg throughout the multi-tube collection sequence and released (deflated to 0 mmHg) only after the last collection tube has filled. This reflects current common nursing practice in the emergency department setting.

Procedure: Sphygmomanometer-Applied Venous Stasis with Varied Release Timing During Phlebotomy

Interventions

Sphygmomanometer-Applied Venous Stasis with Varied Release Timing During Phlebotomy PROCEDURE

A standard aneroid sphygmomanometer is used in place of a conventional tourniquet rubber strap to apply venous stasis at a standardized pressure of 60 mmHg prior to venipuncture. Blood is collected in the following order, per CLSI H03-A6: (1) sodium citrate tube (blue cap, 2.7 mL), (2) serum separator tube/SST (yellow cap, 5 mL), (3) K2-EDTA tube (purple cap, 3 mL). Additional tubes are drawn when ordered by the treating physician as part of routine clinical care, so the total number of tubes per participant ranges from 3 to 5. The intervention variable is the timing of sphygmomanometer release: at the first sign of blood flow into the first tube (Group A, early release) versus after the last tube has filled (Group B, late release).

Also known as: Tourniquet Release Timing; Venous Stasis Duration; Phlebotomy Technique Modification

Early Release Group (Group A); Late Release Group (Group B)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18 years or older
• Presenting to the emergency department and triaged as green (semi-urgent) or yellow (urgent) category according to the Emergency Severity Index (ESI) or equivalent institutional triage system
• Blood collection (venipuncture) indicated as part of routine clinical care by the attending emergency physician
• Ability to provide written informed consent
• Accessible peripheral vein suitable for standard venipuncture, most often in the antecubital fossa but at the operator's discretion an alternative peripheral site such as the dorsum of the hand (not requiring intravenous catheter placement for blood collection)

You may not qualify if:

• Blood collection performed via an existing intravenous catheter or central venous access device
• Critical illness or hemodynamic instability, including triage category red (resuscitation) at the time of blood collection
• Anticoagulant or thrombolytic therapy, or any condition in which collection of a coagulation tube was contraindicated, including a known or suspected coagulation disorder (e.g., hemophilia, thrombocytopenia with platelet count \<50,000/uL)
• Known hemolytic disease, a history of active hemolysis, or another hematological condition associated with baseline elevated hemolysis
• Red blood cell transfusion within the preceding 24 hours
• Pregnancy of any gestational age
• Absence of a peripheral vein suitable for standard venipuncture
• Local pathology preventing collection from the antecubital fossa: infection, hematoma, burn, active upper extremity injury, lymphedema, an arteriovenous fistula, or the side of a previous mastectomy
• Only a single collection tube ordered (the intervention requires at least two tubes, because it is defined by the timing of cuff release relative to tube filling)
• Inability to give informed consent, or declining to participate
• Previously enrolled in this study (re-enrollment not permitted)

Sponsors & Collaborators

• Marmara University Pendik Training and Research Hospital: lead

Study Sites (1)

Marmara University Pendik Training and Research Hospital

Pendik, Istanbul, 34899, Turkey (Türkiye)

Location

Related Publications (4)

• Ayten S, Koşer M, Cumhur A, et al. Comparison of the Hemolysis Rate According to Biochemistry Test Results of Patients Admitted to The Emergency Department with the Results of the Hemcheck Device. Eurasian J Emerg Med. 2025;24(2):126-31. doi:10.4274/eajem.galenos.2024.80947

  BACKGROUND

• Calleja R, Mielke N, Lee R, Johnson S, Bahl A. Hemolyzed Laboratory Specimens in the Emergency Department: An Underappreciated, but Frequent Problem. J Emerg Nurs. 2023 Sep;49(5):744-754. doi: 10.1016/j.jen.2023.06.001. Epub 2023 Jun 27.

  PMID: 37389514 BACKGROUND

• Ersoy S, Ilanbey B; Kirsehir, Turkey. A Single-Center Prospective Study of the Effects of Different Methods of Phlebotomy in the Emergency Department on Blood Sample Hemolysis Rates. J Emerg Nurs. 2023 Jan;49(1):134-139. doi: 10.1016/j.jen.2022.08.005. Epub 2022 Sep 20.

  PMID: 36137822 BACKGROUND

• Wollowitz A, Bijur PE, Esses D, John Gallagher E. Use of butterfly needles to draw blood is independently associated with marked reduction in hemolysis compared to intravenous catheter. Acad Emerg Med. 2013 Nov;20(11):1151-5. doi: 10.1111/acem.12245.

  PMID: 24238318 BACKGROUND

MeSH Terms

Conditions

Hemolysis; Varicose Ulcer; Emergencies

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms; Varicose Veins; Vascular Diseases; Cardiovascular Diseases; Leg Ulcer; Skin Ulcer; Skin Diseases; Skin and Connective Tissue Diseases; Disease Attributes

Study Officials

• Emir Ünal, MD, Assistant Professor

  Marmara University Pendik Training and Research Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Outcome assessors (laboratory technicians performing Hemolysis Index analysis) are blinded to group assignment. Each tube carried its own laboratory information system barcode; the allocated group appeared neither on the request nor on the tube, so group allocation was not accessible to laboratory personnel. Participants and care providers cannot be blinded because of the intervention's procedural nature.
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 23, 2026
• First Posted: June 1, 2026
• Study Start: June 1, 2026
• Primary Completion: July 30, 2026
• Study Completion: July 30, 2026
• Last Updated: August 27, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ANALYTIC CODE
• Time Frame: Following a peer-reviewed publication
• Access Criteria: Reasonable written request to the principal investigator (emirunal@gmail.com).

Locations

TU (1)