A systematic review of the impact of citrate additive to blood collection tubes for the oral glucose tolerance test: implications for gestational diabetes mellitus diagnosis rates — ASN Events
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A systematic review of the impact of citrate additive to blood collection tubes for the oral glucose tolerance test: implications for gestational diabetes mellitus diagnosis rates (#401)

Daniel Yagoub 1 2 , Laura K Buckton 1 , Amanda R Hyne 1 , Ana-Maria Simundic 3 4 , David B Sacks 5 , Andrea Rita Horvath 1 2
  1. NSW Health Pathology - Prince of Wales Hospital, Sydney, NSW, Australia
  2. Faculty of Medicine and Health, University of New South Wales, Sydney, NSW, Australia
  3. Department of Global Medical & Scientific Affairs, Greiner Bio-One, Kremsmunster, Austria
  4. Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
  5. Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, United States

Background

The diagnosis of gestational diabetes mellitus (GDM) by an oral glucose tolerance test (OGTT) is significantly impacted by preanalytical variations in glucose measurement. Glucose concentrations rapidly drop in blood after collection, unless specimen processing adheres to recommendations from the World Health Organisation (WHO) or the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) study. Glucose stability can be preserved in vitro by lowering pH of blood by a citric acid additive. The American Diabetes Association now recommends the use of specimen collection tubes with granulated citrate for routine OGTTs. However, local implementation has been controversial due to concerns about potential over-diagnosis of GDM and higher referral rates to specialist services.

Methods

In order to estimate the impact of citrated blood collection tubes for OGTTs on GDM diagnosis rates, a systematic review was performed comparing paired glucose measurements from “reference” tubes, variably compliant with WHO and HAPO preanalytical conditions, with those containing citrate. Twenty-one primary studies containing 73 individual comparisons were identified. Studies were qualified as ‘adherent’, ‘closely adherent’ and ‘non-adherent’ according to their compliance with WHO/HAPO sample handling recommendations.

Results

Glucose concentrations in citrated tubes had minimal positive average relative biases when compared to reference tubes collected adherently to WHO/HAPO reference conditions (+0.11 mmol/L, +2.0%) or to tubes that had mild delays prior to processing (+0.12 mmol/L, +2.2%). These differences are within acceptable analytical performance specifications for glucose measurements and are unlikely to significantly impact GDM diagnosis rates. In contrast, higher differences were seen when reference tubes were processed non-adherently to WHO/HAPO recommendations (+0.51 mmol/L, +11.6%).

Conclusions

These findings suggest that only sites that were not previously compliant with WHO/HAPO preanalytical conditions will see significant increases in GDM diagnosis rates if tubes containing citrate are used.