ITC IRMA TruPoint Blood Analysis System User Manual

Page 126

A.2

• Delayed tourniquet release during venipuncture can result in falsely

elevated potassium values or dilution effects.

• Hemolysis during sample collection can result in falsely elevated

potassium values.

• The sample was drawn in a syringe that is not compatible with the IRMA

TruPoint system. See Section 2, Syringe Requirements.

• The sample was not well-mixed prior to sample analysis.

• The sample was not injected forcefully enough to displace the calibrant.

• Improper injection technique introduced bubbles into the sample path;

bubbles were not displaced from the sample path prior to analysis phase.

Effects of Physiological Conditions on Test Results

• Blood from patients receiving certain therapeutic treatments, or with

certain physiological conditions, can interfere with the performance of
blood sensors. Refer to standard documents such as "Effects of Diseases
on Clinical Laboratory Tests"

for more information.

• Accuracy of conductivity-based hematocrit measurements are dependent

on a specific range of white blood cell count and total protein
concentration

. Total protein levels may be low in patients on

cardiopulmonary bypass, potentially affecting the conductivity of the
sample, and therefore, the hematocrit results.

When a patient comes off

cardiopulmonary bypass, they may still be hemodiluted. Each facility
should establish protocols to determine when a patient should be
considered to no longer be hemodiluted.

• The calculated total hemoglobin (tHb) is based on assumptions which may

not apply to some physiological conditions.

4, 5

• The calculated parameters for TCO

, HCO

-, BEb, BEecf, tHb, and O

Sat

are based on assumptions which may not apply to some physiological
conditions.

1, 2

• The IRMA TruPoint system measures electrolyte ion activity, and

automatically adjusts electrolyte results to be consistent with results from
indirect methods.

This adjustment is valid only for an assumed activity

coefficient and a typical concentration of plasma water.