However, Gurd and Wilsons criteria for fat embolism become more commonly used when compared to the other two diagnostic criteria. Gurd and Wilsons criteria
Major criteria
Axillary or subconjunctival petechiae
Hypoxaemia PaO2 <60 mm Hg, FIO2 = 0.4
Central nervous system depression disproportionate to hypoxaemia
Pulmonary oedemaMinor criteria
Tachycardia more than 110 beats per minute
Pyrexia more than 38.5 °C
Fat globules present in urine
Changes in renal function (reduced urine output)
Drop in haemoglobin values (more than 20% of the value upon admission)
Drop in haematocrit values
Drop in platelet values (more than 50% of the value upon admission)
Increasing erythrocyte sedimentation rate (ESR) (greater than 71 mm per hour)
Fat globules present in the sputum
Emboli present in the retina on fundoscopyA least two positive major criteria plus one minor criteria or four positive minor criteria are suggestive of fat embolism syndrome. Fat embolism syndrome is a clinical diagnosis. There are no laboratory tests sensitive or specific enough to diagnose FES. Such laboratory tests are only used to support the clinical diagnosis only. Chest X-ray may show diffuse interstitial infiltrates while chest CT scan will show diffuse vascular congestion and pulmonary oedema. Bronchoalveolar lavage has been proposed to look for fat droplets in alveolar macrophages however it is time-consuming and is not specific to fat embolism syndrome. Looking for fat globules in sputum and urine is also not specific enough to diagnose FES. Prevention
For those treated conservatively with immobilisation of long bone fractures, the incidence of FES  is 22%.
Early operative fixation of long bone fractures can reduce the incidence of FES especially with the usage of internal fixation devices. Patients undergoing urgent fixation of long bone fractures has a rate of 7% of acute respiratory distress syndrome (ARDS) when compared to those undergoing fixation after 24 hours (39% with ARDS). However, movement of the fracture ends of the long bones during the operative fixation can cause transient increase of fat emboli in the blood circulation. Cytokines are persistently elevated if the long bone fractures is treated conservatively using immobilisation. The cytokine levels would return to normal after operative fixation. Although ream nailing increases pressure in the medullary cavity of the long bones, it does not increase the rates of FES. Other methods such as drilling of holes in the bony cortex, lavaging bone marrow prior to fixation, and the use of tourniquets to prevent embolisation have not been shown to reduce the rates of FES.Corticosteroid therapy such as methylprednisolone (6 to 90 mg/kg) has been proposed for the treatment of FES, however, it is controversial. Corticosteroid can be used to limit free fatty acid levels, stabilising membranes, and inhibit leukocyte aggregation. A meta-analysis conducted in 2009 reported prophylactic corticosteroids can reduce the risk of FES by 77%. However, there is no difference in mortality, infection, and avascular necrosis when compared to the control group. However, a randomised trial conducted in 2004 reported no differences in FES incidence when comparing treatment with the control group.