Adjustment for High Hematocrit
Whe the Hct is >55% the amount of sodium citrate must be lowered :
Why?
There is less fluid thus less Ca++ in blood
Sodium citrate (mL) = 100 – Hct (%)     x  amt. of blood
                                 595 – Hct (%)
Example
You want to draw a 5.0 mL tube from a patient with a Hct of 60%. How much sodium citrate do you need to have in tube?
Sodium citrate (mL) = 100 – 60     x  4.5
                                 595 – 60
Sodium citrate (mL) = 0.34 mL
Normal ratio of 9:1  in 5 ml draw =
4.5 mL blood + 0.5 mL sodium citrate