Sign in →

Mitochondrial Respiratory Chain Enzyme Analysis (ETC)

Clinical System Name

Miscellaneous

Synonyms

Mitochondrial ETC

Electron Transport Chain

Sample Requirements

Specimen: Muscle Tissue

Container(s): see notes

Preferred Vol:100 mg fresh weight

Minimum Vol: May be able to accept smaller specimens, please contact the laboratory for approval.

Note: A 1 x 0.5 x 0.5 cm sample dissected from the belly of the muscle along the longitudinal plane should be obtained with minimal trauma and no cautery. Sample should be IMMEDIATELY transported to pathology OC.8.901 for weighing and flash freezing in liquid nitrogen.

 

Samples collected at outside hospitals should be flash frozen in liquid nitrogen within 20 minutes of resection and stored at -70C until shipping on dry ice to Seattle Children’s Laboratory, see “Off-Site collection” Instructions below.

 

Processing Instructions

Reject due to:

Spin: N

Aliquot:N

Temp:Frozen

Storage location: Notify Histology immediately when specimen arrives in Lab.  Contact on-call pathologist if Histology is unavailable

Off-site collection: Samples should be flash frozen in liquid nitrogen within 20 minutes of resection, minimizing expose to heat. Store samples at -70C until ready to ship. Ship samples Monday-Thursday on dry ice with overnight delivery.

Stability

Specimen Type Temperature Time
Tissue Room temp

20 min

  On Ice

20 min

 

Frozen at -70°C or colder

10 yr

 

Availability

STAT Performed TAT
N monthly 4 weeks

Muscle biopsies should be scheduled between 0700 and 1500, Mon - Fri at SCH main campus.

Contact the Biochemical Genetics Lab for requests outside of stated availability (206) 987-2216.

Performing Laboratory

Seattle Children's Laboratory    

Department

Department:  Biochemical Genetics

Phone Number: 206-987-2216

 

 

CPT Codes

82657

Methodology

Method: UV-Vis absorbance to measure enzyme function over time.

 

Reference Range

Nine reactions are performed to test functionality of complexes 1-4 as well as citrate synthase and lactate dehydrogenase, for sample quality assurance.

Enzyme

Ref Range (nmol/min/mg)

Mean (nmol/min/mg)

95% Confidence Interval

Complex 1

>8

23

8-38

Complexes 1 and 3

>7

22

7-37

Complex 2

>26

59

26-92

Succinate Dehydrogenase

>19

118

19-218

Complex 3

>14

47

14-80

Complexes 2 and 3

>9

25

9-42

Complex 4

>37

120

37-204

Citrate Synthase

>79

237

79-394

Lactate Dehydrogenase

>575

2178

575-3782

Description

The purpose of this assay is to identify malfunctioning electron transport chain complexes to support clinical evaluation of a defect in energy production. Testing is intended for patients with mitochondrial disease as part of their differential diagnosis for whom neuromuscular pathological evaluation may be ambiguous, DNA analysis was uninformative or identified variants of uncertain clinical significance. Functional enzyme testing may provide supporting evidence for a diagnosis of mitochondrial disease.