Specimen:

Plasma

Collection Medium:

Alternate
Collection Media:

Call laboratory for additional acceptable specimen collection 
containers.

Minimum:

2 ml whole blood in light green top tube or 0.4 ml microtube

Testing Schedule:

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

Analytic Time:

2 hours (upon receipt in laboratory)

Reference Range:

10-20 mcg/ml

Critical value: >20.0 mcg/ml

Test
Limitations:

Criterion: recovery plus or minus 0.8 ug/ml of initial value at 
concentrations less than 8 ug/ml or plus or minus 10% of initial value 
at concentrations greater than 8 ug/ml.

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

Hemolysis: No significant interference from hemoglobin 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.

No significant interference from total protein up to 12 g/dl or 
rheumatoid factor up to 180 IU/ml.

Due to cross-reactivity to 1,3 dimethyluric acid, this assay should not 
be used to quantitate samples from uremic patients (1-5).

The incidence of patients with antibodies to E. coli beta-galactosidase 
is extremely low. However, some samples containing such antibodies can 
result in artificially high theophylline results that do not fit the 
clinical profile.

As with any assay employing mouse antibodies, the possibility exists
for interference by human anti-mouse antibodies (HAMA) in the sample, 
which could cause falsely elevated results.

References:
(1) Breiner R, McComb, Lewis S and Wong SHY, Marzouk N and Kapke GF.
    Positive interference with immunoassay of theophylline in serum of
    uremics, letters to the editor. Clin Chem. 1985;31:1575-1577.

(2) Nelson KM, Mathews SE, Bowers LD. Theophylline concentrations may
    be falsely high in serum of uremic patients, letters to the
    editors. Clin Chem. 1983;29:2125-2126.

(3) Nicot G, Charmes J-P, Lachatre G, et al. Theophylline toxicity
    risks and chronic renal failure. Int J Clin Pharm. 1989;27:398-401.

(4) Opein KE, Ainardi V, Raisys VA, and Smith CM and Messenfer LJ.
    Increase in apparent theophylline concentration in the serum of two
    uremic patients as measured by some immunoassay methods (caused by
    1,3-dimethyluric acid?), letters to the editors. Clin Chem.
    1983;29:1698-1699.

(5) Patel JA, Clayton LT, LeBel CP, et al. Abnormal theophylline levels
    in plasma by fluorescence polarization immunoassay in patients with
    renal disease. Ther Drug Monit. 1984;6:458-460.

Methodology:

EIA (Enzymatic ImmunoAssay)

CPT Code:

80198

See Additional Information:
Chemistry Critical Lab Values