General Tetrahydrobiopterin(THB) ELISA Kit

two product lines: Traditional ELISA Kit and Ready-to-Use ELISA Kit.

	Traditional ELISA Kit	Ready-to-Use ELISA KIT
Product name:	General Tetrahydrobiopterin(THB) ELISA Kit
Method:	Competition
Synonyms:	BH4
Detection range:	0.156-10ng/mL
Target Protein:	THB
Size:	96T/48T
Quality guarantee period:	for 12 months, 16 months
Catalog number:	DL-THB-Ge (traditional)	(ready-to-use)
Assay length	1-2.5Hours	1-2.5Hours
Advantages:	Competitive price. High sensitivity. High stability. 12 months shelf life.	Pre-diluted Detection Reagent A and B Reduction in the number of steps when conducting the test All the reagents can be stored at -20℃ Faster reaction compare to other brands 16 months shelf life
Instruction Manual

1. Overview

Other names：BH4

Function: Tetrahydrobiopterin (BH4, THB, trade name Kuvan) or sapropterin (INN) is a naturally occurring essential cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide synthases.

2. Features

INTENDED USE
The kit is a competitive inhibition enzyme immunoassay technique for the in vitro quantitative measurement of THB in general serum, plasma, tissue homogenates or other biological fluids.

DETECTION RANGE
0.156-10ng/mL. The standard curve concentrations used for the ELISA’s were 10ng/mL, 5ng/mL, 2.5ng/mL, 1.25ng/mL, 0.625ng/mL, 0.312ng/mL, 0.156ng/mL.

SENSITIVITY
The minimum detectable dose of THB is typically less than 0.056ng/mL.
The sensitivity of this assay, or Lower Limit of Detection (LLD) was defined as the lowest protein concentration that could be differentiated from zero. It was determined by adding two standard deviations to the mean optical density value of twenty zero standard replicates and calculating the corresponding concentration.

SPECIFICITY
This assay has high sensitivity and excellent specificity for detection of THB.
No significant cross-reactivity or interference between THB and analogues was observed.
Note: Limited by current skills and knowledge, it is impossible to perform all possible cross-reactivity detection tests between THB and all analogues, therefore, cross reactivity may still exist.

IMPORTANT NOTES
1. Limited by the current conditions and scientific technology, it is impossible to conduct comprehensive identification and analysis tests on the raw materials provided by suppliers. As a result, it is possible there are some qualitative and/or technical risks.
2. The final experimental results will be closely related to validity of the products, operation skills of the end users and the experimental environments. Please make sure that sufficient samples are available.
3. Kits from different batches may be a little different in detection range, sensitivity and color developing time. Please perform the experiment exactly according to the instruction manual included in your kit. Electronic ones on our website are for reference only.
4. Do not mix or substitute reagents from one kit lot to another. Use only the reagents supplied by manufacturer.
5. Protect all reagents from strong light during storage and incubation. All bottle caps of reagents should be closed tightly to prevent evaporation of liquids and contamination by microorganisms.
6. There may be a foggy substance in the wells when the plate is opened at the first time. It will not have any effect on the final assay results. Do not remove microtiter plate from the storage bag until needed.
7. Incorrect procedures during the reagents preparation and loading, as well as incorrect parameter setting for the plate reader may lead to incorrect results. A microplate plate reader with a bandwidth of 10nm or less and an optical density range of 0-3 O.D. or greater at 450 ± 10nm wavelength is acceptable for use in absorbance measurement. Please read the instruction carefully and adjust the instrument prior to the experiment.
8. Even the same experimenter may get different results from two separate experiments. In order to get better reproducible results, the operation of every step in the assay should be controlled. Furthermore, a preliminary experiment before the general assay for each batch is recommended.
9. Each kit has undergone several rigorous quality control tests. However, results from end users might be inconsistent with our in-house data due to some unexpected transportation conditions or different lab equipment. Intra-assay variance among kits from different batches could arise from the above factors as well.
10. Kits from different manufacturers with the same item might produce different results, since we have not compared our products with other manufacturers.
11. Validity period: 12 months.
12. The instruction manual also works with the 48T kit, but all reagents in the 48T kit are reduced by half.

PRECAUTION
The Stop Solution suggested for use with this kit is an acid solution. Wear eye, hand, face, and clothing protection when using this reagent.

You can reference link of the kit as following
https://www.dldevelop.com/uploadfile/data/DL-THB-Ge.pdf

Introduction

Item	Standard		Test
Description	The kit is a competitive inhibition enzyme immunoassay technique for the in vitro quantitative measurement of THB in serum, plasma, tissue homogenates or other biological fluids.		Conform
Identification	Colorimetric		Positive
Composition	Traditional ELISA Kit	Ready-to-Use ELISA KIT	Conform
	Pre-coated, ready to use 96-well strip plate 1	Pre-coated, ready to use 96-well strip plate 1
	Plate sealer for 96 wells 2	Plate sealer for 96 wells 2
	Standard 2	Standard 2
	Diluents buffer 1×45mL	Standard Diluent 1×20mL
	Detection Reagent A 1×120μL	Detection Solution A 1×12mL
	Detection Reagent B 1×120μL	Detection Solution B 1×12mL
	TMB Substrate 1×9mL	TMB Substrate 1×9mL
	Stop Solution 1×6mL	Stop Solution 1×6mL
	Wash Buffer (30 × concentrate) 1×20mL	Wash Buffer (30 × concentrate) 1×20mL
	Instruction manual 1	Instruction manual 1

Test principle

This assay employs the competitive inhibition enzyme immunoassay technique. A monoclonal antibody specific to the index has been pre-coated onto a microplate. A competitive inhibition reaction is launched between biotin labeled the index and unlabeled the index (Standards or samples) with the pre-coated antibody specific to the index. After incubation the unbound conjugate is washed off. Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. The amount of bound HRP conjugate is reverse proportional to the concentration of the index in the sample. After addition of the substrate solution, the intensity of color developed is reverse proportional to the concentration of the index in the sample.

Recovery

Matrices listed below were spiked with certain level of recombinant THB and the recovery rates were calculated by comparing the measured value to the expected amount of the index in samples.

Matrix	Recovery range (%)	Average(%)
serum(n=5)	81-93	86
EDTA plasma(n=5)	80-97	88
heparin plasma(n=5)	90-101	95

Linearity

The linearity of the kit was assayed by testing samples spiked with appropriate concentration of the index and their serial dilutions. The results were demonstrated by the percentage of calculated concentration to the expected.

Sample	1：2	1：4	1：8	1：16
serum(n=5)	82-96%	83-98%	81-99%	93-101%
EDTA plasma(n=5)	88-101%	86-95%	90-102%	80-93%
heparin plasma(n=5)	80-91%	82-90%	95-104%	79-95%

Precision

Intra-assay Precision (Precision within an assay): 3 samples with low, middle and high level the index were tested 20 times on one plate, respectively.
Inter-assay Precision (Precision between assays): 3 samples with low, middle and high level the index were tested on 3 different plates, 8 replicates in each plate.
CV(%) = SD/meanX100
Intra-Assay: CV<10%
Inter-Assay: CV<12%

Stability

The stability of ELISA kit is determined by the loss rate of activity. The loss rate of this kit is less than 5% within the expiration date under appropriate storage condition.
Note:
To minimize unnecessary influences on the performance, operation procedures and lab conditions, especially room temperature, air humidity, and incubator temperatures should be strictly regulated. It is also strongly suggested that the whole assay is performed by the same experimenter from the beginning to the end.

Assay procedure summary

1. Prepare all reagents, samples and standards;
2. Add 50µL standard or sample to each well.
And then add 50µL prepared Detection Reagent A immediately.
Shake and mix. Incubate 1 hour at 37℃;
3. Aspirate and wash 3 times;
4. Add 100µL prepared Detection Reagent B. Incubate 1 hour at 37℃;
5. Aspirate and wash 5 times;
6. Add 90µL Substrate Solution. Incubate 15-25 minutes at 37℃;
7. Add 50µL Stop Solution. Read at 450 nm immediately.