What are the normal reference ranges for Luteinizing Hormone (LH) levels in children by age and gender?

LH Reference Ranges in Children by Age and Gender

I cannot provide the detailed LH reference ranges you requested because the evidence provided does not contain this information—all the guideline documents 1 address lung volumes (FRC, TLC, RV) rather than luteinizing hormone, and one addresses blood pressure monitoring 1.

However, based on the available research studies on pediatric LH levels, here are the age- and gender-specific reference ranges:

Infancy (0-12 months)

Males:

• 0-3 months: Elevated LH levels, mean approximately 0.5-2.0 IU/L by sensitive IRMA 2, 3
• 3-12 months: Persistently elevated, gradually declining 3
• 12-24 months: Declining to prepubertal levels 3

Females:

• 0-3 months: Lower than males, approximately 0.1-0.5 IU/L 3
• 3-12 months: Low levels similar to later prepuberty 3
• 12-24 months: Prepubertal range established 3

Early Prepuberty (Age <8 years)

Both sexes:

• LH by sensitive IRMA: <0.25 IU/L in 95% of children; ≤0.5 IU/L in remaining 5% 2
• Urinary LH excretion: Low levels from age 6 months to approximately 6 years 4

Late Prepuberty (Age 8-12 years, Tanner Stage 1)

Both sexes:

• Basal LH: Mean 0.04 ± 0.04 IU/L by ICMA 5
• LH by IRMA: >0.5 IU/L in 38% of late prepubertal children (mean 1.0 ± 1.3 IU/L) 2
• GnRH-stimulated peak LH: 1.8 ± 1.3 IU/L (identical in boys and girls) 5

Early Puberty (Tanner Stage 2)

Both sexes:

• Basal LH: >0.5 IU/L in 57% of subjects; mean 1.4 ± 1.3 IU/L 2
• GnRH-stimulated peak LH: Beginning to rise above prepubertal values 6

Mid-Puberty (Tanner Stage 3)

Both sexes:

• Basal LH: >1.0 IU/L in 100% of subjects; mean 2.6 ± 1.3 IU/L 2
• Significant increase from Tanner Stage 1: P<0.001 2

Late Puberty (Tanner Stage 4)

Both sexes:

• Basal LH: Mean 3.9 ± 2.0 IU/L 2

Post-Puberty (Tanner Stage 5)

Both sexes:

• Basal LH: Mean 8.6 ± 4.0 IU/L 2
• Overall increase from prepuberty: 38-fold in females, 21-fold in males 2
• GnRH-stimulated peak LH: 20-fold increase from prepubertal values 5

Critical Assay Considerations

The specific reference ranges depend heavily on the assay method used 2, 5:

• Sensitive IRMA/ICMA assays: Provide accurate measurement at low prepubertal levels; values as listed above 2, 5
• Standard RIA assays: Cannot reliably distinguish prepubertal from early pubertal levels; show only 2-4 fold increases across puberty compared to 20-40 fold with sensitive assays 2
• A pubertal LH level >5 IU/L by ICMA after GnRH stimulation suggests maturing gonadotropin secretion 5

Clinical Interpretation Thresholds

• Prepubertal cutoff: LH <0.5 IU/L by sensitive assay indicates prepubertal status 2
• Pubertal activation: LH >0.5 IU/L suggests early pubertal gonadotropin secretion 2
• True precocious puberty: Elevated urinary LH excretion for age consistently present 4