Creatine Kinase (CK) Assay Kit – Bulk Reagents


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Selling unit: per 100ml

Product Name

  1. Common name: Creatine kinase (CK) assay kit (N-acetylcysteine method)
  2. English name: Creatine kinase(CK) detection kit (N-acetyl cysteine)

Reagent Ratio

3:1, 4:1, 5:1, common ratio 4:1, other ratios need to be customized

Intended Use

This kit is mainly used for the in vitro quantification of CK in human serum or plasma.
CK is an important kinase directly related to intracellular energy operation, muscle contraction and ATP regeneration, and it reversibly catalyzes the transphosphorylation reaction between creatine and ATP. It is used in clinical medicine as an in vitro aid in the diagnosis of progressive myotonic dystrophy, polymyalgia, myocardial infarction, hypothyroidism, and hyperthyroidism.

Test Principle

CK can convert creatine phosphate (CrP) and ADP into (Cr) and ATP, and ATP provides high-energy phosphate bonds, which, under the coupling of already glucokinase (HK), induces the conversion of glucose into glucose 6-phosphate, which in turn reacts with NADP+ to produce NADPH with glucose 6-phosphate dehydrogenase (G-6-PD) indicator enzyme. If, in addition to CK, the concentrations of substrate, glucose, NADP+ and the concentrations of both tool enzymes are adequate and appropriate, the rate of NADH production is proportional to the viability of CK, and the viability of CK can be calculated by measuring the rate of NADH production at 340 nm, and the reaction equation is as follows.


ADP + creatine phosphate –→ creatine + ATP


ATP + glucose —→ ADP + G-6-P


G-6-P + NAD+ —–→ Gluconic acid 6-phosphate + NADH + H+

The rate of NADH production was measured at 340 nm and CK viability was calculated.

Main Components

CK assay kit (N-acetylcysteine method) contains the following reagent components.

Creatine kinase (CK) 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 taken care not to be contaminated and the reagents are stabilized 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 ADVIA 1800/2400 series automatic biochemical analyzers.

Sample Request

The most suitable sample is non-hemolyzed serum, stored at low temperature and protected from light. Plasma samples should be anticoagulated with heparin or EDTA. Citrate and fluoride will affect the assay and should be avoided. cK is stable at room temperature (15-25°C) for 2 days; at 2-8°C for 7 days; and frozen (-20°C) for 4 weeks.

Test Method

  1. Reagent preparation: liquid reagents are ready to use out of the bottle.
  2. test conditions: (different test instruments can be requested according to the different parameters on the machine)

Creatine kinase (CK) assay kit

Operation steps.

Creatine kinase (CK) assay kit

  1. Calibration procedure.

Randox calibration serum is recommended. the Randox calibration serum of choice is CK-NAC (IFCC) 37°C.

  1. QC control procedures.

It is recommended that each laboratory establish its own quality control system and select appropriate quality control products for quality control. The measured values of QC products should be within the specified range. If outside the specified range, it is necessary to take appropriate measures or contact the manufacturer.

  1. Calculation.

Sample concentration = (sample ΔA /min) / (standard ΔA /min) × standard concentration

Positive Judgment Value Or Reference Interval

Male: 24 to 194 U/L

Female: 24 to 170 U/L

It is recommended that each laboratory establish its own reference range of normal values.

Interpretation Of Test Results

The determination of CK in serum or 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 and celiac disease ≤ 500 mg/dL did not interfere with the determination.

Product Performance Index

Absorbance of reagent blank: wavelength 340 nm, optical diameter 1.0 cm, temperature 37°C, A0  ≤ 0.50.

Absorbance change rate of reagent blank: △A/min ≤ 0.002 at wavelength 340 nm and optical diameter 1.0 mm.

Analytical sensitivity: The kit tests 100 U/L of the test substance with absorbance change rate ΔA/min ≥ 0.01.

Linearity interval: test serum samples, reagent linearity in the interval of 5 ~ 1000 U/L, linear correlation coefficient |r| should not be less than 0.990; in the interval of 5 ~ 100 U/L, the absolute deviation of linearity should not exceed 10 U/L; in the interval of (100 ~ 1000 U/L, the relative deviation of linearity should not exceed ± 10%.

Precision: repeatability CV ≤ 5%; relative extreme difference between batches ≤ 10%.

Accuracy: Relative deviation ≤ 10%.


  1. 1. This product is for in vitro diagnosis only.
  2. 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. 3. Please dispose of the measured samples and waste liquids in accordance with the relevant national and local laws and regulations.
  4. 4. Do not mix R1 and R2 into a single reagent.
  5. 5. When changing the reagent lot number, please recalibrate.


  1. Witt. C. Trendelenburg, J. Clin. Chemie, Clin. Bioch. 20, 235 (1982)
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