Lactic Acid ( LAC ) Assay Kit – Bulk Reagents


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Selling unit: per 100ml

Product Name

  1. Common name: Lactic acid (LAC) determination kit (enzyme chromatography)
  2. English name: LAC Reagent Kit (Enzyme Colorimetric Method)

Reagent ratio

3:1, 4:1, common ratio 3:1, other ratios need to be customized

Intended Use

This reagent is used for the determination of LAC in human plasma.

In muscle cells, elevated LAC concentrations indicate a metabolic acidosis that may be lactic acidosis. Blood lactate can be increased moderately after exercise, severe anemia, acute wheezing, and convulsions, and it is significantly increased in shock, peripheral circulatory failure, bypass surgery, and cardiac arrest. In diabetic ketosis coma, blood lactate is increased. Severe liver disease can also cause an increase in blood LAC. The severity of lactic acidemia can help reveal the severity of the underlying disease.

Test Principle

Lactate oxidase (LOX) oxidizes lactate to produce pyruvate and hydrogen peroxide, and hydrogen peroxide reacts with 4-aminoantipyrine and TOOS catalyzed by peroxidase (POD) to produce a purple product, which has a maximum absorption peak at 546 nm, and the absorption intensity is proportional to the lactate content in the specimen.

Lactic acid + O 2 Pyruvate + H2 O2

H2 O2  + TBHBA + 4-aminoantipyrine quinoneimine (red) + H2 O

Main Components

Reagent components included in the product.

Lactic acid ( LAC ) assay kit

*Components are not interchangeable in kits with different lot numbers.

*Reagent components not included in the product, but necessary for the test: outsourced normal and abnormal QCs and calibrators.

Storage Conditions And Expiration Date

The kit is stored at 2-8°C away from light and is valid for one year.

Reagents that have been opened are careful not to be contaminated, and reagents are stable in the instrument compartment (2-8°C) for one month.

The reagents must not be frozen.

Applicable Instruments

Hitachi 7180/7600; Olympus AU680/2700; Toshiba TBA120; Myriad BS2000M/480; Siemens ADVIA1800/2400 automatic biochemical analyzer.

Sample Request

For plasma, blood is collected intravenously after fasting and complete rest for at least 2 hours. The anticoagulant should be heparin-sodium fluoride of choice, and the plasma should be separated as soon as possible.

Lactic acid in the samples is stable at room temperature (20-25°C) for 8 hours and at 2-8°C for 14 days.

Test Method

  1. Reagent preparation: liquid reagents are ready to use out of the bottle.
  2. test conditions: (the following parameters are set in accordance with the Toshiba TBA120FR, you can request different parameters on the machine according to different testing instruments)

Lactic acid ( LAC ) assay kit

Operation steps.

Lactic acid ( LAC ) assay kit

Reagents and sample volumes can be increased or decreased in proportion to the requirements of different biochemical analyzers.

  1. Calibration procedure.

The recommended method is the enzyme colorimetric method.

  1. QC control procedures.

It is recommended to use quality control sera produced by Randox Laboratories Ltd UK, Landau Laboratory Diagnostics Ltd. It is recommended that each laboratory establish its own QC system and select appropriate QCs for quality control. The QC values should be within the specified range. If outside the specified range, it is necessary to take appropriate measures or contact the manufacturer.

  1. Calculation.

LAC content (mmol/L) = (ΔAsample – ΔAblank ) × Cstandard / (ΔAstandard – ΔAblank )

Positive Judgment Value Or Reference Interval

Adults: 0.6-2.2mmol/L

The reference interval is derived from the National Clinical Laboratory Practice, 4th edition, and is validated by clinical trials of 150 blood samples from a selected group of normal adults. Each laboratory should establish its own normal reference range based on the region and the population.

 Interpretation Of Test Results

The determination of LAC in human plasma is only one of the indicators used by the clinician to make a diagnosis of the patient. The clinician must also make a comprehensive judgment based on the patient’s physical symptoms, medical history, and other diagnostic items and diagnostic tools.

Limitations Of The Test Method

Ascorbic acid ≤ 30 mg/dL, bilirubin ≤ 40 mg/dL, hemoglobin ≤ 500 mg/dL, celiac disease ≤ 500 mg/dL did not interfere with the determination.

Product Performance Index

Appearance: The appearance of the kit should be neat and tidy, the text symbols are clearly marked, and the reagent bottle is intact; R1 is colorless or light yellow clarified liquid, R2 is colorless or light yellow clarified liquid, both without precipitation, suspension and flocculent.

Absorbance of reagent blank: wavelength 548 nm, optical diameter 1.0 cm, temperature 37°C, A0  ≤ 0.3.

Analytical sensitivity: the kit tests 1.0 mmol/L of the test substance, the absorbance change value ΔA ≥ 0.05.

Linearity range: test serum samples, reagent linearity in the range of 0.2 to 16.0 mmol/L, the linear correlation coefficient |r| should not be less than 0.975; in the interval of 0.2 to 2.0 mmol/L, the absolute deviation of linearity should not exceed 0.2 mmol/L; in the interval of (2.0 to 16.0 mmol/L, the relative deviation of linearity should not exceed ±10%.

Precision: repeatability CV≤ 6.0%; relative extreme difference between batches≤ 10.0%.

Accuracy: Relative deviation ≤ 10%.


  1. This product is for in vitro diagnosis only.
  2. Avoid contamination when using the reagent, the container used must be clean, and please take necessary precautions, do not swallow, and avoid contact with skin and mucous membrane.
  3. Do not mix R1 and R2 into a single reagent.
  4. When changing the reagent lot number, please recalibrate.
  5. There may be differences in the use of reagents from different manufacturers for the same sample.
  6. All sample cassette reaction waste should be treated as an infectious source and the operator needs to take the necessary protective measures.
  7. The reagent contains the preservative sodium azide (toxic), so please rinse thoroughly with water immediately if you accidentally get it in your eyes or mouth or on your skin, and seek medical attention if necessary. Sodium azide can react strongly with copper, lead and other metals to form azide metal, so please dilute the waste solution and flush the drainage pipe when disposing to avoid residue in the drainage pipe.
  8. test tubes and other instruments that have come into contact with the test sample should be disposed of in accordance with medical waste disposal methods.


  1. Kaplan L.A. Et al: Collection and storage of serum lactic acid sample at room temperature without deproten: Clin.Chem, 26, 175-176 (1980).
  2. Bueding E., Goldfarb W.: The effect of sodium fluoride and sodium iodoacetate on glycolysis in human blood: J. Biol. Chem, 141, 539-544 (1941)
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