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Ordering Info & Methodology

Test Code

Cerner Synonyms


MetHb, Methemoglobin

Turn Around Time


Analyzed within 1 hour of receipt, 24/7.

Co-oximetry, Radiometer ABL

Ordering Guide

Component of RMP and ABG

Specimen Requirements

Sample Type

Collection Container

Alternate Collection Containers

Whole Blood

Heparinized Syringe

1 mL

Add on stability
This is the length of time after sample collection that this analyte is stable. Test can be added to a previously collected sample if the time since collection is less than the add on stability time.

Minimum Volume

Add On Stability

Collection and Shipping Requirements

Reference Intervals

Female Reference Interval

Age Category
Reference Interval
≥ 0 y

Male Reference Interval

Age Category
Reference Interval
≥ 0 y
Additional Notes

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Measurement Uncertainty (MU)
Every laboratory value is an estimate of the true concentration of substance. MU is the 95% confidence interval around that estimate. 95% of the time, the true concentration will be within the range of the reported value ±MU. This value is based on analytical variability (precision) and does not reflect other factors such as sample collection and handling which may also affect the result.


Reported sodium = 140 mmol/L
Sodium MU = 1%
Expanded uncertainty = 140 mmol/L ± 1% or 140mmol/L ± 1.4 mmol/L
Interpretation - the true value of sodium in the sample is in the range 138.6-141.4 mmol/L, with 95% confidence.


Measurement Uncertainty

Methemoglobin, if present, will be reported on any blood gas order. If the methemoglobin is not detectable, it does not report.

Hydroxycobalamin, given to smoke exposure victims, results in marked positive bias in methemoglobin.

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