Specimen:

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 mls whole blood in light green top tube or 1 microtube for pediatric 
patients

Testing
Schedule:

24 hrs/day, 7 days a week, including holidays.

Analytic Time:

2 hours (upon receipt in laboratory)

Reference Range:

10-20 mg/dl

Test
Limitations:

Criterion: Recovery within plus or minus 10% of initial values.

Plasma
Icterus: No significant interference up to an I index of 60 
(approximate conjugated and unconjugated bilirubin concentration: 60 
mg/dl).

Hemolysis: No significant interference up to an H index of 1000 
(approximate hemoglobin concentration: 1000 mg/dl)

Lipemia (Intralipid): No significant interference up to an L index of 
1000 (approximate triglycerides concentration: 2000 mg/dl). There is 
poor correlation between turbidity and triglycerides concentration.

Ammonia produced in the cuvette during a GLDH or lactate UV 
determination interferes with the urea/BUN assay. The urea/BUN reagent 
must therefore not be installed on the analyzers together with reagents 
for the GLDH or lactate UV-test. In urine, endogenous ammonium ions 
interfere with the urea/BUN assay. Elevated concentrations can occur 
under acidic conditions (e.g. acidosis).

Great care must be taken to prevent ammonia contamination of the 
specimens and calibrators to be analyzed for urea/urea nitrogen.

Reference:
Glick MR, Ryder KW, Jackson SA. Graphical Comparisons of Interferences 
in Clinical Chemistry Instrumentation. Clin Chem 1986; 32:470-474.

Methodology:

Enzymatic

Sample
Processing:

Centrifuge at 3000 RPM for 10 minutes.
Aliquot plasma into labeled container and cap.

Sample
Storage:

Room temperature or refrigerate if stored overnight.

Transport
Instructions:

Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Ship ambient or refrigerate.

CPT Code:

84520