Laboratory Evaluation for Paresthesia

Initial Laboratory Tests

• Serum calcium (corrected for albumin) and ionized calcium levels should be checked when hypocalcemia is suspected, as hypocalcemia below 8.4 mg/dL with symptoms requires treatment, according to the American Academy of Otolaryngology-Head and Neck Surgery 1, 2
• Magnesium level should be checked as hypomagnesemia can cause hypocalcemia and paresthesia, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery 2
• Phosphorus and intact PTH levels help differentiate causes of hypocalcemia, as suggested by the American Academy of Otolaryngology-Head and Neck Surgery 1
• 25-hydroxyvitamin D level should be checked as vitamin D deficiency is a common cause of hypocalcemia, according to the American Academy of Otolaryngology-Head and Neck Surgery 2

Specialized Testing

• Lyme disease serology should only be ordered in endemic areas or with exposure history and suggestive clinical features, as recommended by the American Academy of Otolaryngology-Head and Neck Surgery 3, 4, 5, 6
• HIV testing should be considered when risk factors are present or other systemic symptoms suggest immunodeficiency, according to the American Academy of Otolaryngology-Head and Neck Surgery 4, 6
• Heavy metal screening should only be ordered with occupational exposure or other toxin exposure history, as suggested by the American Diabetes Association 7

Common Pitfalls to Avoid

• Extensive "neuropathy panels" should not be ordered without clinical indication, as this approach is costly and rarely changes management, according to the American Academy of Otolaryngology-Head and Neck Surgery and the American College of Emergency Physicians 3, 4, 5, 6, 8