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Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays
Published on: January 7, 2016
Low IGF-1 combined with a single clonidine stimulation test as a confirmatory tool for pediatric growth hormone
1Division of Pediatric Endocrinology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Insights
Combining a low Insulin-like Growth Factor-1 (IGF-1) SDS of ≤ -2.5 with a single clonidine stimulation test shows high specificity for diagnosing pediatric Growth Hormone Deficiency (GHD). This approach may reduce the need for a second stimulation test in select cases.
Area of Science:
- Pediatric Endocrinology
- Diagnostic Medicine
- Biochemical Markers
Background:
- Growth Hormone Deficiency (GHD) in children requires dynamic testing due to pulsatile GH secretion.
- The clonidine test is a standard diagnostic tool, but Insulin-like Growth Factor-1 (IGF-1) may offer adjunctive value.
- Diagnosing pediatric GHD often necessitates multiple tests, impacting efficiency and patient burden.
Purpose of the Study:
- To evaluate the diagnostic effectiveness of combining low IGF-1 levels with a single clonidine stimulation test for pediatric GHD.
- To determine optimal IGF-1 standard deviation score (SDS) cutoffs for this combined diagnostic approach.
- To assess the potential of this combination to improve diagnostic accuracy and reduce the need for repeat testing.
Main Methods:
- Retrospective cohort study of 214 children (aged 2-16 years) with short stature.
- GHD confirmed in 63 patients via two GH stimulation tests (peak GH <7 ng/mL).
- Serum IGF-1 SDS analyzed at various cutoffs (≤ -1, -1.5, -2, -2.5, -3) combined with clonidine test results; sensitivity, specificity, PPV, and NPV calculated.
Main Results:
- Combining IGF-1 SDS ≤ -2.5 with a single clonidine test yielded 31.6% sensitivity and 98.6% specificity for GHD.
- This combination demonstrated a positive predictive value (PPV) of 92.3% and a negative predictive value (NPV) of 73.7%.
- An IGF-1 SDS cutoff of ≤ -1.5 showed 60.5% sensitivity and 95.9% specificity.
Conclusions:
- An IGF-1 SDS cutoff of ≤ -2.5 combined with a single failed clonidine test offers high specificity for diagnosing pediatric GHD.
- This combined approach may enhance diagnostic confidence in specific patient groups.
- The findings suggest a potential to reduce reliance on a second GH stimulation test, streamlining diagnosis.
Background:
Growth hormone deficiency (GHD) in children is a complex endocrine disorder that requires dynamic testing for accurate diagnosis due to the pulsatile nature of growth hormone (GH) secretion. The clonidine test is widely used as a standard diagnostic tool due to its favorable safety profile and effectiveness. Insulin-like growth factor-1 (IGF-1) has emerged as a potential adjunct marker; however, its diagnostic accuracy is limited when used alone. This study aims to evaluate the diagnostic effectiveness of combining low IGF-1 with a single clonidine stimulation test for diagnosing pediatric GHD.
Methods:
A retrospective cohort study was conducted at King Chulalongkorn Memorial Hospital, including 214 children with short stature (aged 2-16 years) evaluated between August 2019 and January 2025. GHD was confirmed in 63 patients using two GH stimulation tests (peak GH <7 ng/mL). Serum IGF-1 levels were expressed as standard deviation scores (SDS) and analyzed at cutoff points of ≤ -1, -1.5, -2, -2.5, and - 3 in combination with clonidine test results. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.
Results:
The combination of IGF-1 SDS ≤ -2.5 and a single clonidine test (peak GH < 7 ng/mL) demonstrated a sensitivity of 31.6% and a specificity of 98.6%. The positive predictive value (PPV) was 92.3%, and the negative predictive value (NPV) was 73.7%. Additionally, a cutoff of IGF-1 SDS ≤ -1.5 yielded a sensitivity of 60.5% and specificity of 95.9%.
Conclusion:
An IGF-1 SDS cutoff of ≤ -2.5 combined with a single failed clonidine test demonstrated high specificity for GHD and may provide additional diagnostic confidence in selected patients, potentially reducing the reliance on a second stimulation test.
