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HelpTest Code LAB7086 Mitochondrial Respiratory Chain, Tissue
Performing Section
Mitochondrial Lab
Purpose/Principle
Five different respiratory chain enzyme assays are performed. Citrate synthase and protein are assayed as reference markers. The activity of each enzyme complex is determined by a kinetic spectrophotometric assay over a period of about three to five minutes. Complexes I to IV transfer electrons from one intermediate to the next. In each case, the reduced species absorbs a different amount of light at a particular wavelength. Change in absorbance at 280 nm (coenzyme Q1), 340 nm (NADH) or 550 nm (cytochrome c) or 412 nm (thionitrobenzoate) is used to assay enzyme activity. CoQ1 and decylbenzoquinone (DB) are short-chain analogues of the endogenous hydrophobic CoQ10, which are more suitable for aqueous assay systems. In the assays of complex II, II+III and complex III absorbance increases during the assay, and in other assays absorbance decreases.
Specimen Type
Muscle, Liver, and Heart Tissue:
Sterile container
Specimen Volume
Muscle Tissue
Minimum: 50 mg (150 mg if ordering both BNPage and RCE)
Liver Tissue
Minimum: 50 mg (120 mg if ordering both BNPage and RCE)
Heart Tissue
Minimum: 50 mg (100 mg if ordering both BNPage and RCE)
Processing Instructions
Muscle Tissue:
*Muscle biopsies must be obtained without the use of electrocautery and must be completely processed within 5 to 10 minutes of being excised.
*Tissue must be frozen immediately in liquid nitrogen or on dry ice. The tissue cannot be placed in any preservative including OCT. Sample must be stored in a microvial at -70° C until shipment to the laboratory on dry ice.
Liver Tissue:
*Liver samples can be obtained as a wedge biopsy or as a needle biopsy. If using a needle biopsy, obtain two (2) needle biopsies 14 Gauche Bard monopty instrument 2 cm length.
*Place the liver biopsy in either Parafilm or aluminum foil, then place in a 2 ml cryotube, and close the screw cap tightly. Freeze immediately in liquid nitrogen or on dry ice, and maintain in frozen condition.
*If possible, weigh liver biopsy before placing in the cryotube. If the specimen was not weighed before it was frozen, DO NOT attempt to weigh a frozen sample as the samples degrade very easily. Instead, ship the sample to the Mitochondrial Diagnostic Laboratory without a weight. Lab personnel will weigh the sample.
Heart Tissue:
*Heart biopsies must be obtained without the use of electrocautery and must be completely processed within 5 to 10 minutes of being excised. Post mortem samples have to be obtained within 2 hours of death, but as soon as possible as interpretation will become more difficult with time.
*Tissue must be frozen immediately in liquid nitrogen or on dry ice. They cannot be placed in any preservative including OCT. They must be stored in amicrovial at -70° C until shipment to the laboratory on dry ice.
*If possible, weigh heart biopsy before placing in the cryotube. If the specimen was not weighed before it was frozen, DO NOT attempt to weigh a frozen sample as the samples degrade very easily. Instead, ship the sample to the Mitochondrial Diagnostic Laboratory without a weight. Lab personnel will weigh the sample.
Temperature
Frozen
Test Components
Respiratory Chain, Diagram
Respiratory Chain, Enzyme Activity
Respiratory Chain, Ratio
Reference Range
No reference ranges for listed components.
TAT
90 Days
Additional Notes
Do not ship on weekends or holidays.
Unacceptable Specimens:
-Sample arrives thawed
-Sample arrives in OCT medium or other preservative
-Sample is smaller than the minimum weight requirement
Aliases
Respiratory Chain Enzyme
RCE
CPT
82657