Clinical diagnosis
Only necessary in patients with significant injury or volume of ingestion
Consider:
CBC
Metabolic panel
Lactate
Calcium level (if Hydrofluoric acid exposure)
ECG
May show QT-prolongation if hypocalcemic secondary to Hydrofluoric acid
APAP/ASA levels if concerned about coingestion (suicidal patients)
May show QT-prolongation if hypocalcemic secondary to Hydrofluoric acid
Caustic burn
Caustic ingestion
Cement burn
Caustic eye exposure 
Stingray injury
Caustic dermal burn
Cold injuries
Airbag-related burns