OPTIMedical OPTI CCA-TS - Page 204

Na-2 Operator’s Manual – OPTI CCA-TS
SODIUM ANALYTES
Interferences
The OPTI CCA-TS Na
+
sensor has no measurable interference from K+ variation within the range 0.8-10
mmol/L.
The OPTI CCA-TS Na
+
sensor does exhibit a small interference from Li+. Li+ levels of 1.0, 2.5, and
6.4 mmol/L will cause a positive Na+ bias of 0.9, 1.2, and 1.3 mmol/L, respectively. A syringe sample
anticoagulated with typical amounts of lithium heparin has 1-4 mmol/L of lithium, which offsets the
measured Na+ by less than 1%.
To minimize the interference from lithium, use syringes containing the lowest acceptable heparin level.
Carefully follow the syringe manufacturer’s recommendation regarding proper lling of the syringe.
A partially lled syringe results in excessive lithium concentration.
The OPTI CCA-TS Na
+
results include an appropriate correction for pH at all values of pH.
This correction may introduce an extra source of variability at the extreme values.
Heparin salts are the only acceptable anticoagulants. Other anticoagulants such as citrate, EDTA, oxalate,
and uoride cause signicant interferences to the electrolyte sensors.
The following exogeneous interferents were quantied in tonometered plasma, showing interferences to
dyes which typically have short half-lives within the body before being metabolized by the liver.
Substance amount Na
+
change (mmol/L)
Sodium uorescein 26 mg/dL unstable
Cardio (indocyanine) green 0.5 mg/dL -18
Methylene blue 25 mg/dL -2
Only clear, uncolored quality control materials, such as OPTI CHECK or OPTI CHECK PLUS brand
aqueous controls should be used with the OPTI CCA-TS system. Colored materials, including prociency
testing materials, may interfere with the ion measurement, or fail to be properly aspirated.
Reproducibility
Typical Within-Run (Swr), Between-Day (Sdd) and Total (ST) Precision is determined from 1 run per day
with 2 replicates per run for 20 days on each of two OPTI CCA instruments. Sodium values are expressed
in mmol/L.
Material mean Swr (CV%) Sdd (CV%) ST (CV%)
OPTI CHECK PLUS
(aqueous control solution)
Level 1 117.3 0.10 (0.1) 0.49 (0.4) 0.50 (0.4)
Level 2 142.3 0.11 (0.1) 0.50 (0.4) 0.51 (0.4)
Level 3 158.6 0.11 (0.1) 0.70 (0.4) 0.72 (0.5)
Serum 151.9 0.08 (0.1) 0.92 (0.6) 0.92 (0.6)
Reduced Bovine Hemoglobin 122.3 0.09 (0.1) 0.64 (0.5) 0.65 (0.5)
Solution