Clinical situations affected:
(1) severe hyperlipidemia with chylomicrons
(2) patients receiving intravenous infusions of fat emulsions
The increased turbidity caused by chylomicrons or fat falsely elevates the machine reading of hemoglobin. Since the hemoglobin value is used to calculate the MCH and MCHC these are also elevated.
Plasma Replacement Procedure:
(1) The lipemic specimen is initially run through the automated instrument and the results recorded.
(2) A specimen of blood is aliquoted into a tube.
(3) The height of the sample in the tube is marked by a line.
(4) The sample is then washed with instrument diluent followed by centrifugation and supernatant removal until the supernatant is clear.
(5) An amount of diluent is added to bring the sample to the marked line. This needs to be done as accurately as possible.
(6) The washed sample is then run through the analyzer.
correction factor =
= (RBC count on untreated specimen) / (RBC count on washed specimen)
hemoglobin to report =
= (hemoglobin of washed specimen) * (correction factor)
Parameters reported on untreated specimen:
(1) white blood cell count
(2) red blood cell count
(3) platelet count
(4) hematocrit
(5) MCV
Parameters reported from the washed specimen (untreated specimen results tend to be falsely high):
(1) hemoglobin
(2) MCH
(3) MCHC
