How to Calculate ALOS

ALOS is the average length of stay measured in days. This metric provides guidance to hospital management on the care delivery efficiency in different diagnostic categories, such as how well capacity is being utilized and how quickly patients are being treated and discharged. The average length of stay is calculated by dividing the number of days a patient spends at a hospital by the number of discharges, including deaths.

Instructions

• 1

  Tabulate the date of admission and date of discharge for all patients in a hospital over a period. This period can be a month, three months or longer.

• 2

  Compute the length of stay for each patient by subtracting the date of admission from the date of discharge or death. For example, if a patient is admitted on the 10th and is discharged on the 12th, the length of stay for that patient is two days (12 minus 10). If a patient is admitted and discharged on the same day, the length of stay for that patient is one day.

• 3

  Find the total length of stay by adding the length of stay for each patient. For example, if a hospital admitted and discharged four patients who stayed for 10, 12, five and 11 days during the month, then the total length of stay is 38 days (10 plus 12 plus five plus 11).

• 4

  Calculate the average length of stay for the period. Divide the total length of stay by the number of discharges during the period. To conclude the example, the average length of stay is 9.5 days (38 divided by four).