variety of forms. Some countries use a nationally standardized triage tag, while in other countries commercially available triage tags are used, and these will vary by jurisdictional choice. The most commonly used commercial systems include the METTAG, the SMARTTAG, E/T LIGHT tm and the CRUCIFORM systems. More advanced tagging systems incorporate special markers to indicate whether or not patients have been contaminated by hazardous materials, and also tear off strips for tracking the movement of patients through the process. Some of these tracking systems are beginning to incorporate the use of handheld computers, and in some cases, bar code scanners. Advanced triage In advanced triage, specially trained doctors, nurses and paramedics may decide that some seriously injured people should not receive advanced care because they are unlikely to survive. It is used to divert scarce resources away from patients with little chance of survival in order to increase the chances for others with higher likelihoods. The use of advanced triage may become necessary when medical professionals decide that the medical resources available are not sufficient to treat all the people who need help. The treatment being prioritized can include the time spent on medical care, or drugs or other limited resources. This has happened in disasters such as terrorist attacks, mass shootings, volcanic eruptions, earthquakes, tornadoes, thunderstorms, and rail accidents. In these cases some percentage of patients will die regardless of medical care because of the severity of their injuries. Others would live if given immediate medical care, but would die without it. In these extreme situations, any medical care given to people who will die anyway can be considered to be care withdrawn from others who might have survived (or perhaps had less severe disability from their injuries) had they been treated instead. It becomes the task of the disaster medical authorities to set aside some victims as hopeless, to avoid trying to save one life at the expense of several others. If immediate treatment is successful, the patient may improve (although this may be temporary) and this improvement may allow the patient to be categorized to a lower priority in the short term. Triage should be a continuous process and categories should be checked regularly to ensure that the priority remains correct given the patient's condition. A trauma score is invariably taken when the victim first comes into hospital and subsequent trauma scores are taken to account for