How to identify hemolysis in blood tubes in an adult dialysis patient with chronic kidney disease (CKD) and multiple comorbidities?

Identifying Hemolysis in Blood Tubes During Dialysis

Hemolysis in dialysis blood samples is identified by visual inspection of the plasma for pink or red discoloration, along with clinical symptoms during or immediately after dialysis, and confirmed by laboratory findings of elevated plasma hemoglobin, elevated LDH, and unmeasurable or very low haptoglobin levels.

Visual and Clinical Recognition

Immediate Visual Assessment

• Inspect the plasma portion of blood tubes for pink or red discoloration, which indicates free hemoglobin from lysed red blood cells 1
• Hemolysis can produce plasma hemoglobin concentrations of 3-21 g/L, creating visible color changes in collected samples 1
• Check for hemolysis in samples drawn both during and immediately after dialysis sessions 2

Clinical Symptoms During Dialysis

Patients experiencing acute intravascular hemolysis during dialysis typically present with:

• Malaise, nausea, and headache (present in all cases) 1
• Severe abdominal pain (occurs in approximately 75% of cases) 1
• Pain in the flank region during the dialysis session 2
• Rapid deepening of skin pigmentation in severe cases 2
• Hypotension and cardiac dysrhythmias in massive hemolysis 3

Laboratory Confirmation

Essential Laboratory Tests

When hemolysis is suspected, obtain the following measurements:

• Plasma hemoglobin: Elevated levels (3-21 g/L indicate significant hemolysis) 1
• Lactate dehydrogenase (LDH): Markedly elevated (542-3,300 IU/L in hemolysis cases) 1
• Haptoglobin: Becomes unmeasurable or severely reduced (<0.09 g/L) as it binds free hemoglobin 1
• Potassium: Check for hyperkalemia, which can be life-threatening and may require emergent dialysis 3

Timing of Sample Collection

• Draw samples when symptoms occur during dialysis 1
• Avoid drawing samples from kinked lines or immediately after pump segments, as mechanical trauma can artifactually cause hemolysis 1
• Follow proper predialysis sampling techniques to prevent dilution with saline or heparin, which can confound results 4

Common Causes to Investigate

Mechanical Causes During Dialysis

When hemolysis is identified, systematically check for:

• Kinked blood lines, particularly at the dialyzer inlet port or just below the first arterial line tubing organizer 1
• Blood line kinking can produce visible hemolysis within 30 minutes with plasma hemoglobin reaching 40 g/L 1
• Mechanical damage from stenosis in dialysis blood lines 2
• Poorly fitted pump segments or extra-long pump segments that cause kinking 1
• Recent mechanical thrombectomy procedures of arteriovenous fistulas 3

Equipment-Related Issues

• Dialyzer blood leaks should be documented in treatment records 4
• Review extracorporeal pressures, particularly prepump arterial pressures >200 mmHg 4
• Check blood pump calibration accuracy 4

Critical Pitfalls to Avoid

Sample Collection Errors

• Do not draw predialysis samples after initiating dialysis or from saline/heparin-filled needles, as this dilutes the sample and produces falsely low values 4
• For venous catheters, withdraw 10 mL of blood (3-5 mL in pediatrics) before collecting the sample to avoid heparin contamination 4
• Ensure samples are not drawn from recirculated blood, which can confound all measurements 4

Distinguishing True Hemolysis from Artifact

• In-vitro hemolysis (from traumatic blood draws or delayed processing) produces similar laboratory findings but without clinical symptoms 1
• True intravascular hemolysis during dialysis is accompanied by symptoms (pain, malaise, nausea) occurring during or immediately after the session 1
• Mechanical hemolysis from kinked lines produces both visible plasma discoloration and clinical symptoms simultaneously 1

Immediate Management Considerations

When hemolysis is confirmed:

• Stop dialysis immediately and investigate the blood line setup for kinks or mechanical problems 1
• Monitor for life-threatening complications including hyperkalemia requiring emergent dialysis 3
• Severe hemolysis can produce systemic problems requiring rapid recognition and treatment 2
• Document all findings and equipment issues to prevent recurrence 4