ITC IRMA TruPoint Blood Analysis System - Manual (Page 107)

7.11
BYPASS CORRELATION
QA Users can establish correlation factors for samples from patients on
cardiopulmonary bypass, to adjust IRMA TruPoint patient test hematocrit
results to values that would be expected if samples were run on another
analyzer (i.e., designated reference analyzer). These correlation factors are
based on split-sample blood results from a statistically valid number of
samples.
When established, the user has the option of selecting either “On Bypass”
(bypass correlation factors are used to calculate the hematocrit result) or “Off
Bypass” (bypass correlation factors are not used in the hematocrit measure-
ment) with each patient test.
Collecting bypass correlation data
1. Follow the instructions in steps 1-2 of Section 7-Collecting Correlation
Data.
2. Obtain at least 20 split-sample hematocrit results from at least 5 patients
on cardiopulmonary bypass. USE ONLY SAMPLES COLLECTED
FROM PATIENTS ON BYPASS; PRE- AND POST- BYPASS
SAMPLES SHOULD BE EXCLUDED.
Hematocrit samples collected from cardiopulmonary bypass typically
yield results below 35%. Therefore it is unlikely that samples collected to
establish bypass correlation will span the entire clinical range.
3. Follow the instructions in steps 4-7 of Section 7-Collecting Correlation
Data.
Activating/deactivating the bypass correlation setting
1. Highlight Bypass Correlation from TEST
SETTINGS and press edit .
2. Highlight ”on” or ”off” button and press next .
If ”on” selected, go to “Establishing or
Changing Bypass Correlation Factors”.
Establishing or changing bypass correlation factors
1. Ensure that Bypass Correlation is “on” (see previous section). Press next
from Bypass Correlation screen.
2. Enter slope value (between 0 and 10.000) and press next .
3. Enter intercept value (between -999.00 and +999.99) and press next .