Specimen:

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

Preferred minimum: 2 mL whole blood from light green top tube
Absolute minimum: TWO 0.6 mL microtubes

Testing
Schedule:

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

Analytic Time:

3 hours (upon receipt in laboratory)

Reference Range:

AM (7-9) 4.3-22.4 mcg/dl
PM (3-5) 3.1-16.6 mcg/dl

Critical value: <2.0 mcg/dl

Comments:

Specify collection time.

Test
Limitations:

The assay is unaffected by icterus (bilirubin is less than 60), 
hemolysis (Hb is less than 1900), lipemia (Intralipid Is less than 2700 
mg/dl) and biotin is less than 60 ng/ml (criterion: recovery within 
plus or minus 10% of initial value).

In patients receiving therapy with high biotin doses (i.e. is greater 
than 5 mg/day) no sample should be taken until at least 8 hours after 
the last biotin administration.

No interference was observed from rheumatoid factor (up to 1100 U/ml).

In vitro tests were performed on 17 commonly used pharmaceuticals. No 
interference with the assay was found.

The risk of interference from potential immunological interactions 
between test components and rare sera has been minimized by the 
inclusion of suitable additives.

In rare cases, interference due to extremely high titers of antibodies 
to streptavidin and ruthenium can occur. Elecsys Cortisol contains 
additives which minimize these effects.

Pregnancy, contraceptives and estrogen therapy give rise to elevated 
cortisol concentrations.   In samples from patients who have been 
treated with prednisolone, methyl-prednisolone or prednisone, false 
concentrations of cortisol may be determined.

During metyrapon tests, 11-deoxycortisol levels are elevated. False 
cortisol values may be determined due to cross reactions (see section 
on analytical specificity).

Patients suffering from 21-hydroxylase deficiency exhibit elevated 
21-deoxycortisol levels and this can also give rise to elevated 
cortisol levels.

The time of sample collection must be taken into account when 
interpreting results due to the cortisol secretion circadian rhythm. 
Severe stress can also give rise to elevated cortisol levels.  For 
diagnostic purposes, the Cortisol findings should always be assessed in 
conjunction with the patient's medical history, clinical examination 
and other findings.

Methodology:

Electrochemiluminescent Immunoassay

Sample
Processing:

Centrifuge at 3000 RPM for 10 minutes.
Aliquot plasma into labeled container and cap.
Centrifuge within one hour of draw time.

Sample
Storage:

Refrigerate.

Transport
Instructions:

Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Place dry ice on top of specimen in styrofoam container.

CPT Code:

82533

See Additional Information:
Chemistry Critical Lab Values