Diagnostic Tests and Monitoring

Blood tests

There are a number of blood tests that can provide clues to how the kidneys are functioning.

Urea and creatinine are nitrogen waste products that are regularly moved from the blood to the urine. These levels can increase if a lot of protein or muscle is being built or broken down, and if the kidneys are not working properly.

Albumin is the main protein in the blood. The albumin level is important to keeping fluid in the blood vessels and counteracting edema.

Electrolytes such as sodium (Na+) and potassium (K+) are tested regularly in all patients in intensive care, and can give clues to the function of many different body systems.

The acidity (pH) of the blood and urine can be tested as well to see if a person has a healthy acid-base balance.

Urine samples Urine can be tested for acidity, concentration, and electrolytes. The presence of bacteria, protein or sugars in the urine can indicate the kidney is damaged or diseased. The concentration of the urine in combination with the intake and output allows staff to calculate how quickly the kidneys are filtering the blood.

Intake and Output (I & O)


All patients in the MSICU have their intake and output of fluid measured and compared at least every twelve hours. Intake includes any drinks, IV fluids, or tube feeds. Output is any fluid drained from any tubes, including urine and blood or fluid from chest tubes.


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