Neuron-specific enolase and blood sugar level in ischemic stroke patients

Sir,

The recent publication on neuron-specific enolase and blood sugar level in ischemic stroke patients is interesting. Pandey et al. concluded that “Hyperglycemia predicts an increased risk of poor outcome after ischemic stroke, and it is reflected by a significantly increased level of neuron-specific enolase.”[1] However, there are some concerns on the work. First, the glucose determination in this work is not a fasting blood sample and might be affected by eating. In addition, the measurement by glucose oxidase technique can be interfered by oxygenation status of the patients.[2] These factors must be considered in the interpretation of results. Second, the neuron-specific enolase is a biomarker the levels of which can be increased in certain tumors such as lung cancer.[3] The occult malignancy in stroke patients might also be possible and has to be ruled out. This needs to be considered as well. These limitations are important since increased neuron-specific enolase levels may not have any relationship to hyperglycemia. It is better if the mentioned possible confounding factors are already controlled. Indeed, to determine hyperglycemia in a single analysis of fasting blood sugar cannot reflect the glucose fluctuation. In laboratory medicine practice, to determine the trend of increased blood glucose in a patient, the use of fructosamine or hemoglobin A1C might be more suitable.