Intravenous lipid emulsion interference in coagulation testing: an ex vivo analysis

Area of Science:

• Clinical Chemistry
• Hematology
• Toxicology

Background:

• Intravenous lipid emulsion is a critical rescue treatment for poisonings.
• A known complication is interference with laboratory analyses, particularly coagulation parameters.
• Automated analyzers often rely on optical measurements, which are susceptible to disruption by lipemia.

Purpose of the Study:

• To evaluate the impact of Intralipid on routine coagulation testing ex vivo.
• To determine if specific analytical techniques remain reliable in the presence of lipid emulsion.

Main Methods:

• Human blood samples were diluted with Intralipid to simulate clinical administration (100mL and 500mL).
• Coagulation parameters (prothrombin time, activated prothrombin time, D-dimer, fibrinogen) were tested using three methods: automated analyzer (Sysmex CN6000), manual mechanical endpoint method (Stago KC4 Delta), and automated analyzer after high-speed centrifugation.
• Testing was performed ex vivo on samples from 19 healthy volunteers.

Main Results:

• The automated analyzer (Test-1) failed to analyze samples in the higher dilution (500mL) due to lipemia and only partially analyzed the lower dilution (100mL).
• Both the manual mechanical method (Test-2) and the automated analyzer with prior high-speed centrifugation (Test-3) successfully analyzed all samples.
• Results from Test-2 and Test-3 consistently fell within laboratory reference ranges.

Conclusions:

• Intralipid significantly interferes with automated coagulation testing, rendering results unreliable.
• Manual mechanical endpoint detection or high-speed centrifugation prior to analysis can overcome lipemia-induced interference.
• Clinicians must be aware of this interference and notify laboratories when patients have received Intralipid therapy.