DESCRIPTION

CD38, also known as ADP-ribosyl cyclase 1, is a type II transmembrane glycoprotein with a short N-terminal cytoplasmic tail, a single membrane-spanning domain, and a C-terminal extracellular region with four N-glycosylation sites. The extracellular domain of CD38 has bifunctional enzyme activities that catalyze synthesis of cyclic ADP ribose from nicotinamide adenine dinucleotide (NAD) and hydrolysis of cyclic ADP ribose to adenosine diphosphoribose. CD38 is expressed on a variety of hematopoietic and non-hematopoietic cells and is involved in diverse processes such as generation of calcium-mobilizing metabolites, cell activation, and chemotaxis. In addition to the membrane form, CD38 can also exist as a soluble form (sCD38), which is derived from the membrane form by proteolytic cleavage occurring near the cell membrane.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with HRP) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with HRP also binds to the analyte. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 20 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 24 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	20	1,030.3	31.9	3.1
2	20	247.9	5.9	2.4
3	20	58.6	1.6	2.7

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	24	975.7	28.5	2.9
2	24	242.9	6.1	2.5
3	24	70.1	4.6	6.5

RECOVERY

The recovery of human CD38 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:4	77	73-81
	1:8	79	78-80
Cell lysate	1:320	100	95-103
	1:640	104	103-105

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay. (The cell lysate was initially diluted 1:40. )

		Human serum	Cell lysate
1:2	Average% of Expected	100	100
	Range (%)	-	-
1:4	Average% of Expected	115	100
	Range (%)	112-119	98-102
1:8	Average% of Expected	112	102
	Range (%)	112-113	100-104
1:16	Average% of Expected	79	98
	Range (%)	71-87	96-101

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human CD38 produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
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• Price: USD, per kit (48T / 96T options available)