Serum ethylenediaminetetraacetic acid concentrations in routine samples submitted for biochemical analysis.

BACKGROUND

The aim of the study was to assess the incidence of undetected potassium EDTA contamination in routine blood samples submitted for biochemical analysis.

METHODS

Over a seven-day period, serum EDTA concentrations were measured in all blood samples submitted for routine biochemical analysis.

RESULTS

EDTA contamination was detected in 22 of 4789 samples submitted for analysis (0.46%), of which only seven (0.15%) would have been detected by staff using subjective methods. Detection of low but significant concentrations of EDTA was not necessarily associated with hyperkalaemia or hypocalcaemia. Haemolysis remains the leading cause of non-reporting of analyte results.

CONCLUSION

The presence of EDTA in serum does not always result in spurious hyperkalaemia or hypocalcaemia. Routine measurement of serum EDTA concentrations has the potential to reveal contamination which is not obvious using subjective measures and its routine measurement has the potential to identify minimally contaminated samples.