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

1. 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
2. Reagent Storage and stability
3. Unopened reagent stable at 2-8°C until expiration date.
4. The onboard System temperature reagent is stable for 30 days.
5. Instability or deterioration should be suspected if there are precipitates, visible signs of leakage or
6. contamination, turbidity, or if calibration or controls do not meet the appropriate criteria.

7..Calibration Procedure:

• Multiconstituent Chemistry Calibrator
• Frequency:

1. Reagent lot change
2. QC out of range
3. After service or maintenance
4. 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

1. Reconstitution of QC material with 5 ml Distilled water by using calibrated fixed volume pipette.
2. Leave to stand for 30 min in the dark place.
3. Swirl gently several times during the reconstitution period to ensure that the contents are completely dissolved.
4. 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.
5. Prepare aliquots of 150 µl from the reconstituted QC material.
6. Store these aliquots at -15° C to -20° C.
7. Prior to use, make sure that aliquots should be at room temperature for at least 15 min.

Procedure to run IQC

1. Press Control order
2. Select Assay / Panel, to be run.
3. Select the control/s and its level/s
4. Give Carrier Number and Position number
5. Press F3 / Add order
6. Put respected carrier in RSH rack
7. 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

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:

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