TBA Total bile acid (TBA) Assay Kit （Circulating enzyme method）

Bile acid is the main component of bile, and the increased concentration of bile acid in serum results from liver intake, decreased secretion or portal system shunt. For example, in acute hepatitis, chronic active hepatitis, liver cirrhosis and other diseases, TBA results will be significantly increased. Therefore, serum total bile acid (TBA) level is an important indicator of hepatic parenchymal injury. At present, it is believed that the detection of bile acid in serum is 76% sensitive and 93% specific to the diagnosis of hepatobiliary diseases. In addition, in chronic liver diseases such as liver cirrhosis, the rise of bile acid occurs earlier than the change of albumin, cholesterol, cholesterol ester, and bilirubin. Hence, it is of great significance to the diagnosis of chronic liver disease.

Principle

The bile acid is oxidized by the 3 α-hydroxysteroid dehydrogenase and Thio-NAD⁺, producing 3-ketosteroid and Thio-NADH. The amount of bile acid in serum is amplified during multiple enzyme cycles, and the Thio-NADH produced can be amplified; the content of bile acid in serum can be calculated by measuring the change of Thio-NADH absorbance at 405nm.

Reagents

Storage conditions

Up to expiration date indicated on the label, when stored unopened at 2-8℃ and protected from light.

Once opened, the reagents are stable for 28 days when refrigerated on the analyzer or refrigerator.

Contamination of the reagents must be avoid ed. Do not freeze the reagents.

Once dissolved, the calibrator are stable for 7 days at 2-8℃, the control are stable for 7 days at 2-8℃ , do not freeze.

Sample requirements

Serum is suitable for samples. EDTA plasma, whole blood, hemolysis and urine are not recommended for use as a sample. Freshly drawn serum is preferred specimen.

Method

1.Reagent preparation ： Liquid reagent can be used when opened

2.Measurement：

△A=[∆A/min sample / calibrator]-[∆A/min blank]

Calibration

It is recommended to use the Calibrator from Hzymes and distilled/deionized water for two-point calibration.

Calibration frequency:

After reagent lot changed.

As required following quality control procedures.

Quality control

At least two levels of control material should be analyzed with each batch of samples.Each laboratory should establish its own internal quality control scheme and procedures for corrective action if controls do not recover within the acceptable tolerances.

Reference intervals

Each laboratory should establish its own reference intervals based upon its patient population. The reference intervals measured at 37℃ listed below were taken from literature:

Serum/Plasma: 0~ 10μmo1/L

Interferences/specificity

The following substances were tested for interference with this methodology.

Criterion: Recovery within ±10 % of the initial value.

Reagent blank absorbance

The absorbance of reagent blank at 405nm should be≤0.8 A.

Sensitivity/detection limit

The lowest measurable TBA concentration that can be distinguished from zero is 2μmol/L with 99.7% confidence.

Precision

Within-run:CV≤5%

Between-run:CV≤10%

Linearity range

Sample Type: Serum / Plasma

Conventional Units: 2～180μmol/L;

If the value of sample exceeds180μmol/L, the sampleshouldbedilutedwith9g/L NaCl solution (e.g.1+ 9) and rerun; the result should be multiplied by 10.

Notes

1. For in vitro diagnostic use.

2. Take the necessary precautions for the use of laboratory reagents.

3. Preservative contained. Do not swallow. Avoid contact with skin and mucous membranes.

4. Disposal of all waste material should be in accordance with local guidelines.

5. Material safety data sheet is available on request for professional users.