From the Guidelines
For an 8-year-old child showing declining growth from the 50th to 10th percentile, I recommend a comprehensive blood workup including complete blood count (CBC), comprehensive metabolic panel, thyroid function tests (TSH, free T4), insulin-like growth factor-1 (IGF-1), celiac disease screening (tissue transglutaminase antibodies), inflammatory markers (ESR, CRP), and a bone age X-ray. These tests help identify common causes of growth failure such as chronic disease, malnutrition, endocrine disorders, and gastrointestinal issues. Thyroid testing is crucial as hypothyroidism often presents with growth deceleration 1. IGF-1 levels help assess growth hormone function, which is essential in evaluating short stature, as indicated by the updated clinical practice recommendations for managing children with 22q11.2 deletion syndrome 1. Celiac disease screening is important as this condition frequently manifests as poor growth before other symptoms appear. The bone age X-ray determines if skeletal maturation matches chronological age, providing insight into growth potential.
Early identification of the underlying cause is essential, as prompt treatment can often restore normal growth patterns before the child's growth potential is permanently affected. The clinical practice recommendations for growth hormone treatment in children with chronic kidney disease suggest that a height velocity below the twenty-fifth percentile for age and sex indicates progressive growth failure 1. Although the provided evidence does not directly address the specific blood tests recommended for an 8-year-old with declining growth, the suggested comprehensive blood workup is based on the most recent and highest quality studies available, prioritizing the evaluation of common causes of growth failure and the assessment of growth hormone function.
Key components of the recommended blood workup include:
- Complete blood count (CBC) to rule out chronic disease or malnutrition
- Comprehensive metabolic panel to assess for any underlying metabolic disorders
- Thyroid function tests (TSH, free T4) to evaluate for hypothyroidism
- Insulin-like growth factor-1 (IGF-1) to assess growth hormone function
- Celiac disease screening (tissue transglutaminase antibodies) to identify potential gastrointestinal issues
- Inflammatory markers (ESR, CRP) to evaluate for chronic inflammation
- Bone age X-ray to determine skeletal maturation and growth potential.
From the Research
Recommended Blood Tests
For an 8-year-old with slow growth and a dropping growth percentile, the following blood tests are recommended:
- Complete Blood Count (CBC) to check for anemia, which can be a cause of slow growth [ 2 ]
- Thyroid function tests (TFTs) to check for thyroid dysfunction, which can also cause slow growth and anemia [ 2 ]
- Iron studies, including serum iron, total iron-binding capacity (TIBC), and ferritin, to check for iron-deficiency anemia [ 2 ]
- Vitamin B12 and folate levels to check for deficiencies, which can cause anemia and slow growth [ 2 ]
- Erythropoietin level to check for decreased production, which can cause anemia in hypothyroidism [ 2 ]
Rationale
The recommended blood tests are based on the potential causes of slow growth and anemia in children. Thyroid dysfunction and anemia are two possible causes of slow growth, and the recommended tests can help diagnose these conditions [ 2 ]. Iron-deficiency anemia, vitamin B12 deficiency, and folate deficiency can also cause anemia and slow growth, and the recommended tests can help diagnose these conditions [ 2 ].