This is a retrospective study looking at whether common laboratory investigations can help differentiate between orbital cellulitis (OC) and non-specific orbital inflammation (NSOI). NSOI is a diagnosis of exclusion following negative investigations for systemic diseases such as IgG4-related disease, granulomatosis with polyangiitis and sarcoidosis. OC and NSOI can be difficult to differentiate given their similar presentations. This paper looks at whether laboratory markers – white cell count (WCC) and C-reactive protein (CRP) – can help. Forty-nine patients are included – 26 with OC and 23 with NSOI. The authors found that WCC had a sensitivity of 65.4% for OC and state that a normal WCC cannot exclude OC. They have found that an elevated CRP of more than 20.2 mg/L had a high sensitivity (90.9%) and specificity (90.5%) for OC and conclude that CRP is more useful in diagnosis than WCC. This is an elegant study providing a practical take home message to aid diagnosis and therefore appropriate treatment of two sight threatening conditions.