Which investigations are essential to assess the severity of hypothermia in a primary care patient?

In primary care, to assess the severity of hypothermia, the essential investigation is accurate measurement of the patient's core temperature using an appropriate method. Core temperature measurement should be done at sites that provide either a direct measurement or a reliable estimate of core temperature, such as pulmonary artery catheter, distal oesophagus, urinary bladder, zero heat-flux (deep forehead), sublingual, axilla, or rectum. Peripheral sites like axilla or sublingual may be less accurate if the core temperature is outside the normal range (36.5°C to 37.5°C), so caution is needed in interpretation. Indirect estimates of core temperature (thermometers with correction factors) should not be used. In primary care, practical methods include tympanic or axillary thermometers, but awareness of their limitations is important. Beyond temperature, clinical assessment including vital signs and signs of cardiovascular compromise may be necessary to evaluate severity, but no specific blood tests or imaging are routinely required in primary care for hypothermia severity assessment. Continuous monitoring and documentation of temperature are important if the patient is managed in a healthcare setting.