Thrombopoietin (TPO)

Test Code

CPT Codes

Preferred Specimen
1 mL frozen serum

Minimum Volume
0.5 mL

Cytokine levels may demonstrate diurnal variation. Recommend cytokine levels be determined at the same time of day for improved longitudinal comparison.

Transport Container
Transport tube

Transport Temperature

Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20°: 30 days
Frozen -70°: 7 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Grossly lipemic • Grossly icteric

Immunoassay (IA)

FDA Status
This test was performed using a kit that has not been cleared or approved by the FDA. The analytical performance characteristics of this test have been determined by Quest Diagnostics. This test should not be used for diagnosis without confirmation by other medically established means.

Setup Schedule
Set up: Wed (once a month, First week of every month); Report available: 7-30 days

Reference Range
7-99 pg/mL

Clinical Significance
This test will be used to measure serum TPO level in patients with thrombocytopenia of unknown cause. ITP (Idiopathic Thrombocytopenia purpura) is a common cause of thrombocytopenia. The diagnosis is based on exclusion criteria. Serum TPO levels are normal or only slightly elevated in ITP so that if TPO level is markedly elevated the diagnosis of ITP is strongly in doubt. Markedly elevated TPO levels may occur in individuals with genetic mutations of CD110. New Drugs, non peptide thrombopoietin receptor agonist (CD110) are becoming increasingly used in patients with thrombocytopenia of ITP. The cost of these new drugs is very high. That is why it is important to know levels of TPO. Patients with elevated TPO levels do not respond to treatment with thrombopoietin receptor agonist. Knowing levels of TPO may help in predicting efficacy of response to an extremely expensive stimulating drug used in a wide variety of hematologic disorders. May reduce the need for platelet transfusions with all known complications and reduced cost of blood products by hospital.

Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.