Specimen:

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

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

Quantity is enough for Sodium also.

Testing
Schedule:

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

Analytic Time:

1 hour (upon receipt in laboratory)

Reference Range:

3.5 - 5.0  mEq/l

Pediatric Reference Ranges:

Age       Range    Units
<10 days  3.5-6.0  mEq/l
>10 days  3.5-5.0  mEq/l

Critical value: Adults >16 years       <2.8 mEq/l and >6.2 mEq/l
                Pediatric (0-15 years) <3.0 mEq/l and >6.5 mEq/l

Comments:

Avoid hemolysis.  False elevations may occur in specimens which are not 
processed promptly (to separate serum from RBC's).  Plasma samples 
drawn in heparin tubes have values slightly lower than serum.

Test
Limitations:

Hemolysis:  Potassium is cancelled with a hemolysis index of 100.

Patients over a wide anion gap range demonstrated no significant 
chloride bias from coulometric titrations. Bromide at 0.7 mmol/l gave a 
1 mmol/l chloride response (4).

Selectivity of chloride c artridge (4)(mmol/l of anion required to 
increase chloride results by 1 mmol/l).

A list of substances and conditions known to affect the level of 
sodium, potassium or chloride in vivo is given by both Young et al (5) 
and Friedman et al (6).  No representation is made by Roche Diagnostics 
regarding the completeness of these lists or the accuracy of the 
information contained therein.

References:
(1) Glick MR, Ryder KW, Glick SJ. Interferographs:Users Guide to
    Interferences in Clinical Chemistry Instruments, 2nd ed.
    Indianapolis, IN: Science Enterprises Inc; 1991:35-44.

(2) Tietz NW. Fundamentals of Clinical Chemistry. Philadelphia, Pa:
    3rd ed. WB Saunders Co; 1987:617.

(3) Tietz NW. Clinical Chemistry. Philadelphia, Pa: 2nd ed.,WB Saunders
    Co; 1994:1356, 1364, 1365.

(4) Simmons M, Sugahara K, Watanabe M. Development of an Improved
    Chloride Electrode for the Boehringer Mannheim/Hitachi 700 Series
    Analyzers. Poster session presented at the 1988 National Meeting
    of the American Association for Clinical Chemistry, New Orleans,
    LA, July 27, 1988 (reprints available from Roche Diagnostics
    Corporation).

(5) Young DS, et al. Clin Chem. 1975;21, No 5.

(6) Friedman RB, et al. Clin Chem. 1980;26, No 4.

Methodology:

Ion Selective Electrode

Sample
Processing:

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

Sample
Storage:

Refrigerate.

Transport
Instructions:

Place specimen into zip-lock type bag, seal bag.
Place requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.

CPT Code:

84132

See Additional Information:
Chemistry Critical Lab Values
Chemistry Pediatric Reference Ranges