Neonatal Hypoglycemia Workup

Updated: Apr 07, 2022
  • Author: Hilarie Cranmer, MD, MPH, FACEP; Chief Editor: George T Griffing, MD  more...
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Approach Considerations

Fingerstick glucose levels or bedside testing may lead to overtreatment of hypoglycemia, because the primary error with the chemically treated strips is an underestimation of the serum glucose value.

Serum or plasma glucose levels

Serum glucose level is higher than whole blood glucose level. Whole blood measurements of glucose may underestimate the plasma glucose concentration by approximately 10-15%, because red blood cells (RBCs) contain relatively low concentrations of glucose. Arterial and capillary samples may overestimate the plasma glucose concentration by 10% in nonfasting patients. Hold an extra tube of serum or plasma and refrigerate until laboratory glucose is known.

Serum insulin

When blood glucose is less than 40 mg/dL, plasma insulin concentration should be less than 5 and no higher than 10 µU/mL. This testing may not be available in the emergency department.


Obtain a first voided urine dipstick for ketones. Failure to find large ketones with hypoglycemia suggests that fat is not being metabolized from adipose tissue (hyperinsulinism) or that fat cannot be used for ketone body formation (enzymatic defects in fatty acid oxidation). Send urine for organic acid analysis.

Screening for metabolic errors

Electrospray ionization-tandem mass spectrometry in asymptomatic persons allows earlier identification of clearly defined inborn errors of metabolism. These disorders include aminoacidemias, urea cycle disorders, organic acidurias, and fatty acid oxidation disorders. Earlier recognition of these inborn errors of metabolism has the potential to reduce morbidity and mortality rates in infants with these conditions. [6] This testing may not be available in the emergency department.

Imaging studies

The detection of adenomas by celiac angiography has had limited success. The chance of detecting a tumor blush must be balanced against the potential risk of causing vascular trauma in infants younger than age 2 years. This testing may not be available in the emergency department.