Urine calcium oxalate crystals

What type of ingestion is accompanied by calcium oxalate crystals in the urine?
Ethylene glycol is metabolized to oxalic acid, which may combine with ionized calcium in plasma to form calcium oxalate crystals, which can be evident in the urine. Calcium oxalate can precipitate in the renal tubules and is considered to be involved in ethylene glycol-induced renal injury.

How do you calculate the osmolal gap?
A: Osmolal gap = measured serum osmolality – calculated serum osmolarity. To calculate serum osmolarity use the following formula: Serum osmolarity = ([2 × sodium] + [BUN ÷ 2.8] + [glucose ÷ 18.1]).


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New England Journal of Medicine - Vol. 360, No. 21, May 21, 2009