Estimated blood loss was calculated by following method.

Number of cotton balls used = a

Approximate amount of blood a cotton ball had = 2.5 ml

Amount of blood in cotton balls (c) = 2.5 × (a)

No of gauzes used = b

Approximate amount of blood a gauze had = 10 ml

Amount of blood in gauzes (d) = 10 × (b)

Quantity of blood in cotton balls & gauze (A) = (c + d)

Amount of fluid (Blood and known quantity of saline) collected in the suction bottle = e

Amount of saline used = f

Quantity of blood in suction bottle (B) = (e − f)

Total quantity of blood lost (Estimated blood loss) = A + B.