Insulin-Like Growth Factor-Binding Protein 3 (IGFBP-3), Serum
Synonym(s)
IGFBP-3; Insulin-Like Growth Factor Binding Protein 3, Serum; Somatomedin C Binding Protein
Test ID
IGFB3
General Information
Useful for:
Diagnosing growth disorders
Diagnosing adult growth hormone deficiency
Monitoring of recombinant human growth hormone treatment
As a possible adjunct to insulin-like growth-factor-1 and growth hormone in the diagnosis and follow-up of acromegaly and gigantism
Specimen Type
Serum
Specimen Requirements
Preferred: Red Top
Acceptable: Serum Gel (SST)
Minimum Sample Volume
0.3 mL
Additional Processing Details
Centrifuge promptly
Required Information
Indicate patient's age and sex
Stability
Frozen (preferred): 14 days
Refrigerated: 72 hours
Ambient: 72 hours
Unacceptable Specimen Conditions
Gross hemolysis
Gross icterus
Limitations
Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor-binding protein 3 (IGFBP-3) reference ranges are highly age dependent and results must always be interpreted within the context of the patient's age
Discrepant IGFBP-3 and IGF-1 results can sometimes occur due to liver and kidney disease; however, this is uncommon and such results should alert laboratories and physicians to the possible occurrence of a preanalytical or analytical error
At this time, IGFBP-3 cannot be reliably used as a prognostic marker in breast, colon, prostate, or lung cancer
IGFBP-3 assays exhibit significant variability among platforms and manufacturers. Direct comparison of results obtained by different assays is problematic. Reestablishing a patient's-baseline concentration is preferred if assays are changed
Heterophilic antibodies in human serum can react with the immunoglobulins included in the assay components causing interference with in vitro immunoassays. Specimens from patients with autoimmune diseases or from individuals routinely exposed to animals or animal serum products can demonstrate this type of interference, potentially causing an anomalous result. The assay reagents have been formulated to minimize the risk of such interference; however, potential interactions between rare sera and test components can occur. For diagnostic purposes, the results obtained from this assay should always be used in combination with the clinical examination, patient medical history, and other findings.
Note: Puberty onset, ie, the transition from Tanner stage I (prepubertal) to Tanner stage II (early pubertal), occurs for girls at a median age of 10.5 (+/-2) years and for boys at a median age of 11.5 (+/-2) years. There is evidence that it may occur up to 1 year earlier in obese girls and in African-American girls. By contrast, for boys there is no definite proven relationship between puberty onset and body weight or ethnic origin. Progression through Tanner stages is variable. Tanner stage V (young adult) should be reached by age 18.