LDL Cholesterol Reagents

LDL Cholesterol Reagents are used for the in-vitro quantitative determination of Direct LDL Cholesterol in human serum and plasma. This direct reagent kit is designed for routine lipid profile testing in clinical chemistry laboratories and uses an end point method measured at 578 nm. For broader background on LDL cholesterol and lipid testing, see the CDC page on cholesterol and NHLBI: What is Blood Cholesterol?. As part of a wider Clinical Chemistry Reagents range, this product can also be explored alongside HDL Cholesterol Reagents and Cholesterol Reagents.

Pack size: 1 × 40 ml
Shelf life: 18 months
Storage: 2° to 8°C

Product Overview

This LDL cholesterol reagent kit is based on a direct measurement principle for LDL-C in serum and plasma. The method works in two stages: first, non-LDL cholesterol is eliminated through enzymatic reactions, and then LDL cholesterol is specifically measured after release by detergents in Reagent 2. The intensity of the quinone pigment formed is proportional to the cholesterol concentration when measured at 578 nm.

As part of a broader lipid testing workflow, this product can be used alongside our Clinical Chemistry Reagents, HDL Cholesterol Reagents, and Cholesterol Reagents.

Intended Use

This reagent kit is used for the in-vitro quantitative determination of Direct LDL Cholesterol in human serum and plasma.

Test Principle and Reaction

The reagent is based on two stages:

1. Elimination of non-LDL cholesterol
   Cholesterol esters are converted to cholesterol and fatty acids by cholesterol esterase. Cholesterol is then oxidised by cholesterol oxidase, and hydrogen peroxide is broken down by catalase.
2. Specific measurement of LDL cholesterol
   LDL cholesterol is released by detergents in Reagent 2 and then measured through enzymatic reactions that form a quinone pigment. The intensity of the quinone pigment is proportional to the cholesterol concentration when measured at 578 nm.

Kit Contents

• Reagent 1: R1 Reagent
• Reagent 2: R2 Reagent
• Reagent 3: Direct LDL Calibrator (separately provided)
• Product Insert: 01 No.

Reagent Preparation and Stability

Reagent 1 and Reagent 2 are ready to use.

Calibrator: Reconstitute with 1 ml of distilled water. Let it stand for 30 minutes at room temperature and dissolve by gently swirling to avoid foam formation.

Storage and Stability:

• Reconstituted calibrator is stable for 7 days at 2–8°C.
• Store kit contents immediately at 2–8°C after use.

Specimen Collection and Storage

Use fresh serum that is free of haemolysis.

Precautions

• Follow the storage conditions mentioned on the kit.
• Do not freeze or expose the reagents to higher temperature.
• Bring all reagents to room temperature before the assay.
• Store the kit contents immediately at 2–8°C after use.
• Avoid contamination during assay process.
• Use clean glassware free from dust or debris.

Test Procedure (Manual)

Pipette into clean dry test tubes labelled Blank (B), Calibrator (C), and Test (T):

• R1 Reagent: 375 µl in B, C and T
• Calibrator: 5 µl in C
• Sample: 5 µl in T

Mix and incubate for 5 minutes at 37°C.

Then add:

• R2 Reagent: 125 µl in B, C and T

Mix and incubate for 3 minutes at 37°C. Measure the absorbance of calibrator and test against reagent blank at 578 nm.

Calculations

LDL-C Concentration = (Abs of Test / Abs of Calibrator) × Calibrator Concentration

Normal Values

Serum/Plasma

• < 130 mg/dl: Desirable
• 130–159 mg/dl: Border line high risk for CHD
• > 160 mg/dl: High risk for CHD

Each laboratory should establish its own normal range representing its patient population.

Linearity

This procedure is linear up to 1000 mg/dl. If the value exceeds this limit, dilute the sample with normal saline (NaCl 0.9%) and repeat the assay. Multiply the result by the dilution factor.

Quality Control

For accuracy, it is necessary to run known controls with every assay.

FAQs

What are LDL Cholesterol Reagents used for?

They are used for the in-vitro quantitative determination of Direct LDL Cholesterol in human serum and plasma. For general context on LDL cholesterol and why it is measured in lipid testing workflows, refer to the CDC cholesterol overview andNHLBI: What is Blood Cholesterol?.

What method does this LDL cholesterol reagent kit use?

The IFU describes an end point direct method measured at 578 nm.

Can these LDL cholesterol reagents be used with other lipid profile tests?

Yes. This product can be contextually paired with HDL Cholesterol Reagents and Cholesterol Reagents as part of a lipid testing workflow.

What is the stated linearity of the LDL cholesterol assay?

The IFU states that the procedure is linear up to 1000 mg/dl.

What specimen type is required?

The IFU specifies human serum and plasma, with fresh serum free of haemolysis noted under specimen collection.

How should the kit be stored?

Store the kit at 2–8°C and return contents immediately to 2–8°C after use.