Plasmapheresis removes plasma proteins. The rate of removal can be calculated by measurement of plasma levels before and after each session.
removal rate for a plasma protein =
= ((plasma concentration before plasmapheresis) - (plasma concentration after plasmapheresis)) / (plasma concentration before plasmapheresis)
apparent amount of protein removed in mg =
= ((plasma concentration before in mg/dL) - (plasma concentration after in mg/dL)) * (plasma volume in mL) / 100
Factors impacting accuracy of the calculation:
(1) distribution of the protein in extravascular space
(2) replacement fluid used during plasmapheresis
If fresh frozen plasma (FFP) or albumin is used for replacement:
amount of protein replaced =
= (concentration of protein in mg/dL in replacement fluid) * (volume of fluid in mL) / 100
This must be taken into account when calculating the amount of protein removed.
total amount of protein removed in mg =
= (apparent amount of protein removed in mg) - (amount of protein replaced in mg)
Alternatively the concentration of the protein can be measured in the removed fluid.
amount of protein removed =
= (concentration of protein in removed fluid in mg/dL) * (volume of fluid in mL) / 100
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Specialty: Clinical Laboratory, Hematology Oncology, Immunology/Rheumatology