PT
– Interference - 1
Ratio of blood to sodium citrate:
Factors that interfere with PT testing:
Normal ratio:
9:1
Hematocrit >55%:
Recollect if outside
of acceptable limits
Adjust amount of
sodium citrate and recollect
See specimen
requirements slide in this unit
Clots in specimen:
Must be redrawn
Visible hemolysis:
Must be redrawn
Icteric or lipemic specimen:
May need to run on
electro-mechanical device
Heparin therapy:
Use
heparin-insensitive or heparin-neutralizing reagent or Hepsorb
treated specimen