magnesium [Laboratory Service Sir T Hospital , Bhavnagar ]

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                      Magnesium Examination Procedure
**1.Purpose of examination:** 
Magnesium estimation from serum or plasma by Enzymatic method.

**2.Responsibility and Authority:** 
  * Calibration: Technician 
  * Quality Control: Technician 
  * Routine operation: Technician 
  * Overall Monitoring: Quality Manager

**3.Sample Details:** 
  * Type of Sample: Serum,  Plasma
  * Type of container and additives: Plain without any additives 
  * Patient Preparation: As per Primary Sample Collection Manual [[sample_collection_manual|]]
  * Stability: At Room temperature 18°–28°C (64°–82°F) stability ≤ 24 hours
  * Handling and transport: As per Primary Sample collection manual 
  * Storage: 24 hours at 2-8° C

**4.Required Equipment:** 
Centrifuge, Auto-Pipette, Disposable Tips, Disposable sample cups, FullyAuto Chemistry Analyzer

**5.Required reagents:**
R1:Isocitrate dehydrogenase 2.2 U/mL
D-Isocitrate potassium salt 1.47 mg/mL
R2 :NADP 8.37 mg/mL

**6..Reagent Handling**
  - Remove any air bubbles present in the reagents with a new applicator stick, or allow the reagents to settle at the appropriate storage temperature to allow the bubbles to dissipate. To minimize volume depletion, do not use a transfer pipette to remove bubbles
  - Reagent Storage and stability
  - Unopened reagent stable at 2-8°C until expiration date.
  - The onboard System temperature reagent is  stable for 30 days.
  - Instability or deterioration should be suspected if there are precipitates, visible signs of leakage or
  - contamination, turbidity, or if calibration or controls do not meet the appropriate criteria.

**7..Calibration Procedure:**
  * Multiconstituent Chemistry Calibrator 
  * Frequency:
  - Reagent lot change
  - QC out of range
  - After service or maintenance
  - Replacement in any parts of Instrument
  * **Procedure:**
  * Start the equipment.WDI abbotte fully.docx
  * Calibrators are ready to use.
  * Put calibrator 15-20 minutes at room temperature  
  * Prior to use, mix the contents by inverting the vial. Do not shake the vial to prevent foam formation. 
  * Take a 150 µl calibrator solution in separate aliquots.
  * Go to the calibration and give the calibration order.
  * Verify calibration with at least two levels of controls.
  * If control results fall outside acceptable ranges,root cause analysis or recalibration may be necessary.

**8.Quality control Procedure:**
Name: Bio Rad Level 1 , 2 
Frequency: As per Quality Control Procedure

**Procedure for Reconstitution of IQC** 
  - Reconstitution of QC material with 5 ml Distilled water by using calibrated fixed volume pipette.
  - Leave to stand for 30 min in the dark place.
  - Swirl gently several times during the reconstitution period to ensure that the contents are completely dissolved.
  - Prior to use, mix the contents by inverting the vial. Do not shake the vial as the information of foam should be avoided. Ensure that no lyophilized material remains un-reconstituted.
  - Prepare aliquots of 150 µl from the reconstituted QC material.
  - Store these aliquots at -15° C to -20° C.
  - Prior to use, make sure that aliquots should be at room temperature for at least 15 min.


**Procedure to run IQC**
  - Press Control order 
  - Select Assay / Panel, to be run.
  - Select the control/s and its level/s
  - Give Carrier Number and Position number
  - Press F3 / Add order
  - Put respected carrier in RSH rack
  - Check IQC results, in case outliers call residents.

**9.Principle of the procedure used for examinations:**
  * Magnesium present in the sample is a cofactor in an enzymatic reaction with isocitrate dehydrogenase. The rate of increase in absorbance at 340 nm, due to the formation of NADPH, is directly proportional to the magnesium concentration.

**Sample Preparation:**
  * Required SampleVolume: 150 µl of the sample 
  * Temperature: 37° 
Take 150-200µl of the sample from Primary tube to the secondary aliquot. Write the sample ID on the aliquot. 

**10.Procedure to run Patient sample**
  * Press Patient order 
  * Select Assay /Panel, to be run.
  * Give Carrier Number and Position number
  * Press F3 / Add order
  * Put respected carrier in RSH rack

**11.Performance Characteristics:** 
  * Linearity:of 0.60 to 9.50 mg/dL
  * The limit of detection (LOD):0.10 mg/dL
  * The limit of quantitation (LOQ):0.16 mg/dL
  * Unit: mg/dL

**Normal and critical ranges:**

**Magnesium**
^0-6 y^1.7-2.3^mg/dL^
^7-12 y^1.7-2.1^mg/dL^
^>12 y^1.6-2.6^mg/dL^

**12.Laboratory Clinical interpretation:**
Hypomagnesemia results in impairment of neuromuscular function, carbohydrate intolerance, and cardiac arrhythmias.
Hypermagnesemia results in hypotension, bradycardia, and respiratory depression, among other conditions.

**13.Interference and cross reaction:**
  * No interference from lipemia up to 2482 MG/DL
  * NO interference from hemoglobin up to 1200 MG/DL. 
  * No interference from conjugated  bilirubin up to 56.5 mg/dl.
  * No interference from unconjugated up to 60.9 mg/dl
  * No interference from calcium up to 28.00 mg/dl
  * No interference from copper up to 6.5 micro./ml
  * No interference from iron up to 641 micro/dl
  * No interference from L-Dopamine up to 5.0 mg/dl
  * No interference from triglyceride up to 3647 mg/dl
  * No interference from zinc up to 4.3 micro./ml
  * No interference from glucose up to 1311 mg/dl
  * No interference from ascorbic acid up to 3.0 mg/dl
 

**14.Potential source of variation:** 
**Turn around time (TAT):**
  * Routine: 6.0 hours
  * Urgent: 2.0 hours

**15.Recording of observation:**
  * Software backup 
  * Machine raw data

**16.Storage & Disposal of waste:** Follow storage & discard procedure

**17.Environmental & Safety control:**
Follow the universal work precautions. Reagent R1 contains sodium azide 0.1% as a preservative. Avoid contact with skin & mucosa. 

**18.References:**
  - US department of labor, Occupational safety and health administration.
  - US department of health and human services. Biosafety in MIcrobiological and biomedical laboratories.
  - Burtis CA,Ashwood ER,editors,Tietz Textbook of clinical chemistry
  - Kaplan LA,Pesce AJ editors. Clinical Chemistry Theory, Analysis, and Correlation, 3rd ed

|**Printed copy of this document is considered uncontrolled.** It should be compared with controlled electronic copy before use|

^ Name of Laboratory : Laboratory Services Sir T. Hospital (LSSTH),Bhavnagar ^^^^
^Document No.1^**Document Name**: Magnesium Examination Procedure^**Unique ID**:LSSTH /BIOCHEM/ SOP-5^^
^Issue No. : 01^Issue Date :30/04/2024^Page No.^^
^Amend No.^ Amend Date ^Prepared by: Section Incharge^Approved & Issued by: HOD,Biochemistry^