A Not So Crystal-Clear Case

A physician from an outside hospital called our laboratory for help regarding interpretation of cerebrospinal fluid (CSF) results. She was confused by a report from her laboratory that reported the presence of “calcium oxalate crystals 3+” upon microscopy examination of a CSF sample (Figure 1). The CSF findings were as follows: protein concentration, 0.9 g/L, (reference interval, 0.15–0.35 g/L); chloride, 106 mmol/L (reference interval, 120–130 …