Specimen

Plasma

Collection Medium:

Minimum:

1 mL plasma from a Special Z-GI preservative collection tube obtained 
from reference laboratory.  Mailouts has these tubes, call 356-8593.

Delivery Instructions:

Submit specimen to laboratory as soon as possible after
collection period is completed.

Analytic Time:

1 week

Reference Range:

Long-acting repeatable (LAR) dose-response levels: mean octreotide 
level + or - 2 SD for patients on octreotide LAR for 3 or more months 
(steady-state). The following represent trough levels measured 
immediately before an injection of LAR.
10 mg/month:  1,153 + or - 748 pg/ml
20 mg/month:  2,518 + or - 1,020 pg/ml
30 mg/month:  5,241 + or - 3,004 pg/ml
60 mg/month:  10,926 + or - 5,530 pg/ml

Comments:

Contact Commercial Mailouts at 356-8593 to obtain collection tubes for 
this testing.  No other specimen collection container is acceptable by 
the reference laboratory.

Patients should be fasting for 10-12 hours prior to specimen 
collection.  Antacid medications or medications that affect intestinal 
motility should be discontinued, if possible, for at least 48 hours 
prior to collection.

This test is useful only for those patients being treated with 
octreotide acetate. No special preparation is needed for this test. For 
optimal results, blood for this test should be drawn immediately before 
the patient's next injection of octreotide LAR (trough levels).

Clinical Significance:
Octreotide (Sandostatin, Novartis Pharmaceutical Company) is used for 
the control of symptoms associated with functional neuroendocrine 
tumors. Frequent measurement of the octreotide levels may be useful in 
guiding therapy in patients with poorly controlled symptoms or those 
patients experiencing tumor growth during LAR therapy. Octreotide 
levels in blood need to be in a specific range to be effective. 
Measuring octreotide immediately prior to the monthly LAR injection 
will determine trough levels of the drug in your blood.

Methodology:

Octreotide is measured by direct radioimmunoassay. There is no 
cross-reactivity with native somatostatin-14 or somatostatin-28. The 
also is no cross-reactivity with lanreotide, and this test should not 
be used to measure blood levels of this drug.

CPT Code:

83519