LDL CHOLESTEROL DIRECT REAGENT KIT
BEACON
INTENDED USE:
The reagent kit is intended for the in-vitro quantitative determination of LDL Cholesterol in Serum / Plasma.
PRINCIPLE:
Cholesterol is released from LDL particles and enzymatically determined.
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Cholesterol Ester + H₂O
(Cholesterol esterase) → Cholesterol + Fatty acids -
Cholesterol + O₂
(Cholesterol oxidase) → Cholest-4-en-3-one + H₂O₂ -
H₂O₂ + 4-Aminoantipyrine + Phenol
(Peroxidase) → Quinoneimine dye + H₂O
The intensity of the colored complex formed is proportional to the LDL cholesterol concentration and is measured at 575 nm.
REAGENTS:
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Reagent 1 (R1): Buffer
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Reagent 2 (R2): Enzymes
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Standard: LDL Cholesterol
MATERIALS REQUIRED BUT NOT PROVIDED:
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Semi auto / Fully auto analyzer
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Micropipettes & Tips
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Incubator
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Distilled water
SAMPLE:
Serum or plasma. Avoid hemolysis.
PROCEDURE (37°C):
| Blank | Standard | Sample | |
|---|---|---|---|
| Reagent | 375 µl | 375 µl | 375 µl |
| Standard | — | 25 µl | — |
| Sample | — | — | 25 µl |
Mix and incubate for 5 minutes at 37°C.
Measure absorbance at 575 nm against reagent blank.
CALCULATION:
LDL-C (mg/dl) = (Abs. of Test / Abs. of Standard) × Standard concentration
NORMAL VALUES:
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< 130 mg/dl : Desirable
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130–159 mg/dl : Borderline high
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≥ 160 mg/dl : High risk of CHD
Each laboratory should establish its own reference range.
CLINICAL SIGNIFICANCE:
LDL particles are lipoproteins that transport cholesterol to tissues. LDL cholesterol is considered a major risk factor for coronary heart disease and atherosclerosis. Elevated LDL levels are associated with increased risk of cardiovascular disease.
PREPARATION OF REAGENT & STABILITY:
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Mix R1 and R2 as per instructions.
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Working reagent is stable for 7 days at 2–8°C.
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LINEARITY:
The procedure is linear up to 1000 mg/dl.
Samples exceeding this value should be diluted with normal saline (NaCl 0.9%) and retested. -
INTERFERENCES:
No interference observed up to:
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Hemoglobin: 500 mg/dl
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Bilirubin (conjugated): 40 mg/dl
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Bilirubin (unconjugated): 40 mg/dl
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Ascorbic Acid: 5 mg/dl
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Triglycerides: 1000 mg/dl BIBLIOGRAPHY:-
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NCEP ATP III Guidelines
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Burtis & Ashwood, Tietz Fundamentals of Clinical Chemistry
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Other standard clinical chemistry references
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