A study by Brigham and Women’s Hospital and Harvard Medical School shows that centrifuged lithium heparin plasma gel separation tubes (PST) are significantly more stable in glucose measurement than the commonly used sodium fluoride/potassium oxalate (NaF-KOx) tubes. The results have a direct impact on the diagnosis of diabetes and prediabetes.

The research team led by Nicole V. Tolan compared uncentrifuged LiHep and NaF-KOx samples with immediately centrifuged PST samples over a period of eight hours at room temperature. This showed that NaF-KOx samples showed a significant drop in glucose in the first 90 minutes, which was comparable to uncentrifuged LiHep samples. In contrast, glucose levels in the centrifuged PST samples remained stable for up to 240 minutes.

The authors recommend rejecting NaF-KOx and uncentrifuged samples after 60 minutes for fasting glucose and OGTT studies. Instead, PST tubes should be used and centrifuged within 30 minutes of blood draw. This is particularly relevant in outpatient settings with transport delays.

The study underlines that NaF-KOx tubes do not stop glycolysis immediately and are also not automation-friendly. PST tubes, on the other hand, better meet the requirements for reliable glucose measurement and are suitable for automated laboratory processes.

The results were published in the journal Diabetes Care (DOI: 10.2337/dc25-2197). They provide practical recommendations for preanalytics in fasting glucose and oral glucose tolerance tests and are intended to help avoid falsely low glucose levels that can lead to misdiagnosis or inappropriate therapy adjustments.

Original Paper:

Preanalytic Considerations for Preventing In Vitro Glycolysis: Practical Recommendations for Fasting and Glucose Tolerance Testing | Diabetes Care | American Diabetes Association

Editor: X-Press Journalistenbüro GbR

Gender Notice. The personal designations used in this text always refer equally to female, male and diverse persons. Double/triple naming and gendered designations are used for better readability ected.