Reference Range

If TTAB positive (>10) and IgA normal:
"Celiac disease possible. Consider referral to gastroenterology specialist for consideration for biopsy."

If IgA is age-specific normal and TTAB is equivocal (4-10 U/mL): 
"Equivocal serology, celiac disease cannot be excluded. Referral to gastroenterology specialist recommended for additional evaluation.”
 

If IgA is age specific normal and TTAB is negative (<4.0 U/mL): 
"Negative Serology. Celiac disease unlikely. Approximately 10% of patient with celiac disease are seronegative. Patients who are already adhering to a gluten-free diet may be seronegative. If celiac disease is highly clinically suspected, referral to gastroenterology for additional evaluation is recommended.”
 

If IgA > 6.7 mg/dl, but lower than age-specific normal and TTAB is negative (<10 U/mL): “Low total serum IgA; Recommend referral to gastroenterology specialist for additional evaluation.”
 

If IgA is below detection (< 6.7 mg/dl) and TTAB is negative (<10 U/mL):
“Total serum IgA deficiency; Recommend referral to gastroenterology specialist for additional evaluation.”