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Paediatric Laboratory Medicine

Complex I+III

Clinical Significance

To determine the rate of cytochrome c reduction in mitochondria as a result of electron transfer from NADH to cytochrome c (mitochondrial Complex I+III activity)

Test Name

Complex I+III

Alternate Name/ Synonym

  • NADH Cytochrome C Reductase (Rotenone - Sensitive)

Gene Name

  • Caused by mutations in up to 60 nuclear genes, and 7 mitochondrial genes.

Division

Mitochondrial Disease

Method

Spectrophotometric Measurements at 550nm

Turn Around Time

  • Fibroblasts: 3 weeks - 3 months
  • Tissue Biopsies: Fresh - 5 business days
  • Tissue Biopsies: Frozen - 1 month

Disease/Condition

  • Systemic Mitochondrial Syndromes
  • Leigh's

Specimen Type

  • Endocardial biopsy
  • Fibroblast mitochondria
  • Muscle mitochondria
  • Kidney homogenates
  • Liver homogenates
  • Muscle homogenates

Minimum Specimen Requirements

  • 1 dish for subculturing
  • 20 dishes for mitochondrial isolation from fibroblasts
  • 30-50 mg from muscle biopsy/autopsy for testing on muscle homogenate 
  • 250-300 mg for mitochondrial isolation from fresh muscle biopsy

Optimal Collection Time

  • For fibroblasts, frozen biopsies: anytime
  • Fresh biopsy: until 2:30 pm, Monday-Friday

Storage/Transportation

For fresh biopsy: call to book (ext. 205989) at least 24 hours in advance for full Mitochondrial Enzyme screening on isolated mitochondria. Pick up from Pathology.

Special Requirements

For fresh biopsy: call to book (ext. 205989) at least 24 hours in advance for full Mitochondrial Enzyme screening on isolated mitochondria. Pick up from Pathology.

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Reference Range

  • Fibroblast mitochondria: 23.65-77.82 nmol/mg/min, CI+III/CS: 0.55-1.30
  • Muscle homogenate: 0.52-2.37 µmol/min/g wet wt, CI+III/CS: ≥0.1, CI+III/CII+III: ≥0.2
  • Muscle mitochondria: 55.20-363.08 nmol/mg/min, CI+III/CS: ≥0.1, CI+III/CII+III: ≥0.2
  • Kidney homogenate: 0.22-1.70 µmol/min/g wet wt
  • Liver homogenate: 0.63-7.57 µmol/min/g wet wt
  • Endocardial homogenate: 44.30-137.02 nmol/mg/min

All rates reported in combination with CS rates.