This package insert follows the Pharmaceuticals, Medical devices and Other Therapeutic Products Act of Japan.
In Vitro Diagnostics
Marketing Approval No.21300AMZ00422000** Revised: March 2021 (7th edition)* Revised: November 2018 (6th edition)

This package insert must be read carefully prior to use.
Creatinine assay kit(Classification No.: 30161002)

diseases.
Assay Principle ＊＊1. Assay Principle
In the first reaction, creatine in samples isdegraded into water and oxygen by the action ofcreatine amidinohydrolase, sarcosine oxidase, andcatalase.
In the second reaction, creatinine in samples isconverted to creatine by the action of creatine
amidinohydrolase and then sarcosine is producedby the action of creatine amidinohydrolase. In
the presence of hydrogen peroxide produced fromsarcosine by sarcosine oxidase and peroxidase(POD), oxidative condensation of N-ethyl-N-(3sulfopropyl)-3-methylaniline (TOPS) and 4aminoantipyrine is allowed to occur. The
concentration of creatinine is determined bymeasuring the absorbance of the resulting quinone
dye (red-purple).

Pureauto S CRE-L
General Precautions ＊＊1. This product is for in vitro diagnostic use, andmust not be used for any other purposes.
2. Clinicians should make a comprehensive clinicaldecision based on assay results in conjunction withclinical symptoms and other examination results.
3. For the effects of an administered drug on themeasured value, carefully read the Precautions for
Use in the package insert of the drug, especiallythe section about the effects on laboratory testresults. Please also read carefully the “2.
Interfering Substances,” in the “ProceduralPrecautions” section, as well as “2. Precautions forAssessment” in the “Assessment of Assay Results”
section, of this package insert.
4. This product should be used only as directed in thispackage insert. Reliability of results cannot beguaranteed if there are any deviations from theinstructions in this package insert.
5. If the reagent accidentally comes in contact witheyes and/or mouth, rinse immediately with ample
water as first aid, and consult the doctor if
required.
6. Carefully read the operating instructions for eachtype of automated analyzers prior to using thisproduct. Parameters for each type of analyzers areavailable, and can be requested from SEKISUIMEDICAL CO., LTD. if required.
7. Perform a quality control test prior to assay toensure accuracy.

First reaction:
Creatine amidinohydrolase
Creatine + H2O
Sarcosine +Urea
Sarcosine oxidase
Sarcosine+O2+H2O Glycine+HCHO+H2O2
2H2O2Catalase

O2 + 2H2O

Second reaction:
Creatinine

Creatinine amidehydrolase
Creatine

Creatine amidinohydrolase
Creatine + H2O
Sarcosine +Urea
Sarcosine oxidase
Sarcosine+O2+ H2O Glycine+HCHO+H2O2

Description (Kit Components) ＊＊Component: Ingredients
CRE-L Enzyme Solution 1:
Creatine amidinohydrolase
Sarcosine oxidase
N-ethyl-N-(3-sulfopropyl)-3methylaniline
CRE-L Enzyme Solution 2:Creatinine amidehydrolase
4-AminoantipyrinePOD
H2O2+TOPS+4-Aminoantipyrine Quinone
dye (red-purple color)
2. Features
1) Liquid reagents, ready-to-use.
2) The enzymatic method is employed．
3) Applicable to various automated analyzers.
＊＊

Procedural Precautions ＊1. Properties of Samples and Sampling Methods
1) Samples
Serum, plasma, or urine (1:21 dilution) may
be used.
2) Storage of samples3)
If the isolated serum or plasma sample cannot
be tested on the same day, specimens should
be stored as follows:
2–10oC: for tests within 1 week
≤ -20oC: for tests after more than 1 week
Bring samples to room temperature (15–30oC)
before use.
Urine samples should be tested on the sameday.

Intended Use
Measurement of creatinine concentration in serum,plasma, or urine
Creatinine is a degradation product of high-energy
creatine phosphate that is released into the bloodfrom the muscles and nerves. Creatinine is filtered by
the renal glomeruli and is excreted in the urine,
mostly without reabsorption.
Because the blood level of creatinine is increased inpatients with renal failure, uremia, and heart failure,
it plays an important role as an index of kidney
function in the diagnosis and evaluation of these12. Interfering substances
1) Assay results are not affected by free bilirubin(up to 20 mg/dL), conjugated bilirubin (up to20 mg/dL), hemoglobin (up to 200 mg/dL),ascorbic acid (up to 40 mg/dL), creatine (up to20 mg/dL), or glutathione (up to 50 mg/dL).
2) In high immunoglobulin samples, turbidity
may be produced after adding the first reagent,and negative errors may be given to analyticalresults.
3) Sodium azide that is added as a preservative
for samples may give positive errors toanalytical results.
3. Others
1) Always use Serum Multicalibrator (SEKISUI),
Seronorm Multicalibrator or Anaserum CRE
Standard Solution for calibration.
2) Precautions for assay range
If the concentration of sample exceeds assay
range, dilute the sample with saline and repeat
the measurement.

5 mg/dL of creatinine.
2. Accuracy: 92–108% of the expected assay value
3. Within-run Reproducibility:Coefficient of variation ≤5%(Test methods used for 1.–3.are in-house methods.)
4. Measurement Range9) (On Hitachi 7150
automated analyzer)
0.02–150 mg/dL
5. Correlation9)
1) Serum
N=50 r=0.999 y=1.03x–0.10
Control method: Approved in vitro diagnostic(enzymatic method)
2) Plasma N=50 r=0.999 y=1.03x–0.09
Control method: Approved in vitro diagnostic(enzymatic method)3) Urine (diluted 1:10)
N=50 r=0.999 y=1.03x– 0.26
Reference method: Approved in vitro diagnostic(enzymatic method)
6. Standard Material
SRM914（NIST）

Dosage/Administration (Assay Procedure) ＊＊1. Preparation of reagents
Reagent (1): CRE-L Enzyme Solution 1 is readyto use.
Reagent (2): CRE-L Enzyme Solution 2 is readyto use.
2. Assay Procedure
This product is compatible with various types ofautomated analyzers. An example of the assay
procedure is indicated below.

Precautions for Use or Handling
1. Precautions for Handling (to Ensure Safety)
1) All samples used in the test should be handled
as a material possibly infected with HIV, HBV,HCV, or other viruses. To prevent infection, use
disposable gloves and avoid mouth pipetting
during the test.
2) CRE-L Enzyme Solution 2 contains 0.05%
sodium azide. If any reagent is accidentally
ingested or comes into contact with the eyes orskin, immediately take first-aid measures suchas rinsing with water and seek medical
treatment if necessary.
2. Precautions for use
1) This product should be stored as directed,
without freezing. Freezing can deteriorate thereagents, which can produce inaccurate results.
Therefore, avoid using the reagents which havebeen previously frozen.
2) Do not use expired reagents. Use of suchreagents cannot guarantee the reliability ofmeasurement values.
3) Do not replenish the reagents.
4) Do not perform the assay under direct sunlight
3. Precautions for Disposal
1) Before disposal, used samples and theircontainers must be immersed in sodium
hypochlorite solution at a concentration ofgreater than 0.1% for longer than 1 hour or
autoclaved at 121ºC for 20 minutes.
2）To prevent infections from spilled samples orsolutions containing samples, wipe the spilledarea thoroughly with disinfectants such assodium hypochlorite solution at a concentrationof greater than 0.1%.
3) The reagents and treated samples should bediscarded as medical waste or industrial waste
according to the waste disposal regulations.
4) The reagents should be disposed of inaccordance with the Water Pollution Control act
or related regulations.
5) CRE-L Enzyme Solution 2 contains 0.05%
sodium azide. Sodium azide may react withlead or copper pipes and produce highly

37CSample Reagent (1)+6 μL
270 μL

Measurement(Absorbance I※)

5 minReagent (2) 37C90 μL
5 min※Measurement(Absorbance II※)

Calculation ofconcentration

Absorbance I and II: The difference in absorbance
between 800 nm and 546 nm
Calibration material: Serum Multicalibrator(SEKISUI), Seronorm Multicalibrator orAnaserum CRE Standard Solution (Manufacture'sassigned value)
Reagent blank: Purified water or saline

Assessment of Assay Results ＊＊1. Reference standard range4)
Serum: Male 0.65–1.07 mg/dL
Female 0.46–0.79 mg/dL
Urine: 0.5–1.5 g/day
2. Precautions for Assessment
There may be reactions or interfering reactions
with non-target substances. If assay results appear
to be unreliable, repeat the measurement (ifnecessary, after dilution) or try another analyticalmethods.
Performance ＊＊1. Sensitivity
1) Reagent blank: absorbance being equal to or
lower than 0.05
2) Sensitivity: The absorbance is 0.12–0.18 per2

explosive metallic azide. When disposing of
this product, flush it away with copious
amounts of water.
4. Other precautions
Do not use the containers for other purposes.
Storage and Shelf Life
1. Storage temperature: 2–10C
2. Shelf life: 1 year from the date of manufacture(The expiration date is printed on the outer package.)
Packaging
Name
Package
CRE-L Enzyme(1) Solution 1
2 × 200 mL
Pureauto S
CRE-LCRE-L Enzyme(2) Solution 2
2 × 100 mL
Constituent reagents are available in otherconfigurations. For further details please contact
SEKISUI MEDICAL CO., LTD.
References ＊＊1) Yoshimura M. et al.: Jpn J Clin Med (extraedition), 53, 464, 1995. Japanese.
2) Osawa S.: Med Tech, 26, 389, 1998. Japanese.
3) Sasaki M. et al.: Sampling of constituents of thehuman body. Tokyo: Kodansha; 1972. Japanese.
4) Kanai M, editor. Kanai’s manual of clinicallaboratory medicine. 35th ed. Tokyo: Kanehara
Shuppan; 2020. Japanese.
5) Sasaki T: Mod Med Lab, 15, 259, 1987. Japanese.
6) Suzuki M., Yoshida M.：Clin. Chim. Acta. 143,147, 1984.
7) Yasuhara M et al.: Mod Med Lab, 18, 31, 1990.
Japanese.
8) Japan Society of Clinical Chemistry: Jpn J Clin
Chem, 23, 326, 1994. Japanese.
9) SEKISUI MEDICAL CO., LTD. In house data.
Japanese.
Contact
SEKISUI MEDICAL CO., LTD.
international@sekisui.com

Manufacturer
SEKISUI MEDICAL CO., LTD.
1-3, Nihonbashi 2-chome, Chuo-ku, Tokyo, Japan"Pureauto" and "Anaserum" are trademarks orregistered trademarks of SEKISUI MEDICAL CO.,LTD. in Japan and/or other countries.
All other brands, product names and service names
are trademarks or registered trademarks of theirrespective companies.

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