Test Directory

High proinsulin concentrations have been associated with benign or malignant β-cell tumors of the pancreas and endocrine pancreatic tumors associated with MEN-1. Elevated proinsulin levels have been observed in individuals with impaired glucose tolerance even in the absence of abnormal glucose or C-peptide levels. Elevated proinsulin levels have been found to be a positive risk factor for the development on NIDDM. Most patients with β-cell tumors have increased insulin, C-peptide, and proinsulin concentrations, but occasionally only proinsulin is elevated. Despite its low biological activity, proinsulin may be increased sufficiently to produce hypoglycemia. In addition, a rare form of familial hyperproinsulinemia, due to impaired conversion to insulin, has been described. Increased proinsulin concentrations may also be detected in patients with chronic renal failure, cirrhosis, or hyperthyroidism.

Specimen Type: Serum

Collection Container: Gold Top, Serum Separator

Alternate Collection Container: Red Top, Plain

Desired Specimen Volume: 0.6 mL

1. Collect a gold top, serum separator tube via venipuncture.

1. Separate serum from cells.
2. Transfer 0.6 mL of serum to a LabCorp PP transpak frozen purple tube and freeze immediately.
3. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Baseline proinsulin levels should be collected after a 12-hour fast.

Transport to the laboratory frozen. 

• Nonfrozen specimen
• Nonserum specimen
• Gross hemolysis
• Gross lipemia

 See patient report.