Cytomegalovirus IgM Antibody Detection Kit (Enzyme-Linked Immunosorbent Assay)

Instructions for the Cytomegalovirus IgM Antibody Detection Kit (Enzyme-Linked Immunosorbent Assay Capture Method)
[Product Name]
Generic Name: Cytomegalovirus IgM Antibody Detection Kit (Enzyme-Linked Immunosorbent Assay)
[Packaging Specifications]
48 servings per box, 96 servings per box.
[Intended Use]
This product is intended for the qualitative detection of cytomegalovirus IgM antibodies in human serum or plasma.
Cytomegalovirus (CMV) belongs to the Betaherpesvirinae subfamily of the Herpesviridae family. Its primary modes of transmission are direct or indirect contact, including exposure to the saliva, genital secretions, urine, and breast milk of infected individuals; it can also be transmitted transplacentally or via iatrogenic routes. Following infection, CMV IgM antibodies remain detectable in serum for 4 to 6 months, and in some cases may persist for several years, whereas CMV IgG antibodies generally persist lifelong. Detection of CMV IgM antibodies is useful for diagnosing acute CMV infection, but it cannot distinguish between primary and secondary infections. Detection of CMV IgG antibodies helps determine whether a person has been exposed to CMV and enables appropriate interventions for susceptible populations. Testing for CMV antibodies is particularly important for immunocompromised patients, pregnant women, organ transplant recipients and donors, as well as blood donors.
[Principle of Assay]
Principle of the enzyme‑linked immunosorbent capture assay: A microtiter plate is coated with a monoclonal antibody against the human IgM μ chain. The serum or plasma to be tested is added to the wells, where any IgM antibodies present in the sample bind to the anti‑human IgM μ chain antibodies immobilized on the plate, forming an antibody–secondary antibody complex. After washing, a cytomegalovirus antigen conjugated to an enzyme is added, resulting in the formation of an (antibody–secondary antibody–enzyme‑conjugated antigen) immune complex. Following another wash, a chromogenic substrate is introduced; under enzymatic catalysis, a colorimetric reaction develops. The intensity of this color reaction is measured with a microplate reader, allowing for the qualitative detection of cytomegalovirus IgM antibodies in the sample.
[Main Ingredients]
1. Components included in this kit
Serial No. Component Name Main Ingredient Usage Method Package Quantity
96 servings per box, 48 servings per box
1 Microtiter plate pre-coated with anti-human IgM-μ chain antibody. The plate is pre-coated with mouse monoclonal anti-human IgM-μ chain antibody. It can be separated into individual wells for direct use, available in 96-well and 48-well formats.
2 Cytomegalovirus Antigen–Enzyme Label: Horseradish peroxidase (HRP)-labeled recombinant cytomegalovirus antigen; borate buffer containing preservatives and protein stabilizers. Ready to use. 6.5 mL × 1 vial, 3.5 mL × 1 vial.
3 Cytomegalovirus IgM Antibody Positive Control: Human plasma or serum positive for cytomegalovirus IgM antibodies; borate buffer containing 0.02% thimerosal and a protein stabilizer. For direct use. 1.0 mL × 1 vial, 1.0 mL × 1 vial.
4 Cytomegalovirus IgM Antibody Negative Control: Human plasma or serum negative for cytomegalovirus IgM antibodies; borate buffer containing 0.02% thimerosal and a protein stabilizer. For direct use. 1.0 mL × 1 vial, 1.0 mL × 1 vial.
5 Cytomegalovirus IgM Antibody Critical Control: Cytomegalovirus IgM‑positive human plasma or serum; borate buffer containing 0.02% thimerosal and a protein stabilizer. For direct use. 1.8 mL × 1 vial, 1.8 mL × 1 vial.
6 Color-developing solution A: citric acid, hydrogen peroxide. Use directly. 6.5 mL × 1 bottle, 3.5 mL × 1 bottle.
7 Color-developing solution B: citric acid, tetramethylbenzidine (TMB). Ready to use. 6.5 mL × 1 bottle, 3.5 mL × 1 bottle.
8 Concentrated Detergent (10×) Phosphate-buffered solution, containing 0.5% Tween‑20, 10× concentrated. Dilute 10-fold with distilled or deionized water before use. 50 mL × 1 bottle 50 mL × 1 bottle
9 Sample Diluent (IgM): Borate buffer containing glycerol. For direct use. 50 mL × 2 bottles, 50 mL × 1 bottle.
10 Stop solution: 0.5 mol/L H2SO4 solution. Use directly: 6.5 mL × 1 bottle, 3.5 mL × 1 bottle.
11 Sealed bags 1 piece 1 piece
12 sealing films, 4 pieces, 4 pieces
13 Recording Paper 1 copy 1 copy
Note: Enzyme conjugates, positive controls, negative controls, and cutoff controls must be those provided with the kit; products from other batch numbers may not be used. The sample diluent (IgM) is compatible with all of our company’s ELISA kits for IgM antibody detection. Chromogen A, chromogen B, stop solution, and concentrated wash solution are universal reagents and can be used with all of our company’s ELISA kits.
2. Materials required but not yet provided:
Distilled water or deionized water
Microplate washer
10 μL to 100 μL, 1 mL pipettes with disposable tips
37°C constant-temperature equipment
Microporous Oscillator
Microplate reader
A timer with a duration of 60 minutes or longer
[Storage Conditions and Shelf Life]
Store at 2°C to 8°C, protected from light; shelf life is 12 months.
After opening, any unused microtiter plate should be placed in a sealed bag and stored at 2°C to 8°C. Each component, once opened, should be used within one month.
Production date and expiration date: See label for details.
[Applicable Instruments]
A microplate reader with wavelengths of 450 nm and 630 nm.
[Sample Requirements]
Serum or plasma samples should be collected in accordance with the clinical blood‑collection technical guidelines. Samples stored at room temperature should not exceed 8 hours; if testing is performed after 8 hours, samples must be kept at 2°C–8°C. For storage exceeding one week, maintain samples at −20°C or lower and avoid repeated freeze–thaw cycles. This assay is suitable for samples containing EDTA, sodium citrate, sodium heparin, sodium oxalate, or double‑oxalate anticoagulants; however, there are currently no experimental data regarding the suitability of samples containing other types of anticoagulants. Although bilirubin, hemoglobin, and triglycerides do not significantly interfere with the assay results, samples exhibiting jaundice, hemolysis, or hyperlipidemia should still be avoided. Clearly contaminated samples must not be used for testing.
[Testing Method]
1. Precautions During the Experiment
1.1 When the kit components are removed from refrigeration, they should be allowed to equilibrate at room temperature (20°C–25°C) until no condensation is visible before use. Any unused coated plates after opening should be stored in a sealed bag.
1.2 During storage and incubation, direct exposure to strong light should be avoided. All reagent vials must be tightly capped to prevent evaporation and contamination.
1.3 To prevent microbial contamination and cross-contamination of reagents or samples, disposable pipette tips should be used and not reused.
1.4 Before aliquoting the standard and enzyme conjugate, gently shake to ensure thorough mixing; prior to sample addition, use a microplate shaker to thoroughly mix the diluted samples.
1.5 Strictly adhere to the specified incubation time and temperature. If the interval between adding samples to the first well and the last well is too long, it will result in varying “pre-incubation” times, thereby significantly compromising the accuracy and reproducibility of the measurements.
1.6 At the end of the washing step, invert the microplate onto a paper towel and gently tap it to ensure that all wells are free of wash buffer and to prevent foam formation. If using an automated plate washer, be sure to operate it correctly.
2. Experimental Preparation
2.1 Preparation of Reagent Kit Reaction Reagents
2.1.1 Microporous Strip
Secure the required number of microplate strips to the plate holder, and store the remaining strips in a sealed bag.
2.1.2 Washing Solution
Dilute the concentrated detergent in a clean graduated cylinder. Add 50 mL of concentrated detergent to distilled or deionized water up to a final volume of 500 mL, and mix thoroughly.
2.1.3 Other Liquid Components
Use directly; shake gently before use to ensure thorough mixing.
2.2 Sample Preparation
Sample 1:100 dilution: Take 10 µL of the sample to be tested and add it to a small test tube containing 1 mL of sample diluent (IgM), then mix thoroughly.
3. Testing Procedure
3.1 For each assay, include one blank well (unless using dual-wavelength detection, in which case a blank well is not required), one positive control well, one negative control well, and three cut-off control wells. The blank well should contain no sample or enzyme conjugate; add only wash solution, developing reagent A, developing reagent B, and stop solution. The positive, negative, and cut-off controls are used directly at 100 μL per well. Add 100 μL of the diluted sample to all other wells. Incubate at 37°C ± 1°C for 60 minutes.
3.2 Discard the liquid from the wells, then add washing solution to each well until it is completely filled (approximately 300 μL per well). Remove the excess by tapping the plate gently and blotting dry, repeating this process three times. Except for the blank well, add 50 μL of enzyme‑labeled reagent to each well and incubate at 37°C ± 1°C for 60 minutes.
3.3 Discard the liquid from the wells, wash the plate three times as described above, and after blotting dry, add 50 μL of developing reagent A and 50 μL of developing reagent B to each well. Incubate at 37°C ± 1°C in the dark for 10–15 minutes, then add 50 μL of stop solution to each well and gently shake the microplate to ensure thorough mixing.
3.4 Single-wavelength detection: Zero the instrument using the blank well, then measure the absorbance (A) at 450 nm with a microplate reader.
Dual-wavelength detection: Read the absorbance values at 450 nm and 630 nm using a microplate reader, and calculate the net absorbance as A450nm – A630nm.
4. Reference Range
The negative control A-value shall be ≤0.15; the average A-value of the cutoff control shall be between 0.20 and 0.80, with an A-value ratio of cutoff control to negative control ≥2.0; and the positive control A-value shall exceed the average A-value of the cutoff control. Only under these conditions is the assay considered valid; otherwise, the results are invalid and the assay must be repeated.
[Positive Judgment Value]
Calculate the S/CO value as follows: S/CO = Sample A value / Mean of the critical control A values.
Reactivity (R): S/CO ≥ 1.1
Suspicious (S): 0.9 < S/CO < 1.1
Negative (N): S/CO ≤ 0.9
[Interpretation of Test Results]
1. A reactive result indicates an acute or recent cytomegalovirus infection. For reactive and indeterminate results, it is recommended to repeat sampling and testing in 1–2 weeks, while also performing CMV‑IgG antibody testing to dynamically monitor changes in antibody levels.
2. The test results are for clinical reference only; clinicians should integrate the patient’s medical history, symptoms, and other laboratory findings to arrive at a diagnosis.
[Limitations of the Analytical Method]
1. Microbial contamination of samples or reagents, as well as cross-contamination between reagents, may lead to erroneous results.
2. No cross-reactivity was observed between this product and antinuclear antibody–positive serum, rheumatoid factor–positive serum, serum from patients with chronic hepatitis B, or IgM‑antibody–positive serum against the pathogens listed in the cross‑reactivity panel; however, experimental data on cross‑reactivity with other pathogens are currently unavailable.
[Product Performance Specifications]
1. Sensitivity, specificity
This product was evaluated using 1,016 samples from diverse populations, demonstrating a sensitivity of 99.9% and a specificity of 99.8%.
2. Precision
The within-run coefficient of variation (CV, %) shall not exceed 15% (n = 10).
3. Cross-reactivity
No cross-reactivity was observed between this product and sera positive for antinuclear antibodies, rheumatoid factor, chronic hepatitis B, or IgM antibodies against the following pathogens: Toxoplasma gondii, measles virus, rubella virus, and herpes simplex viruses types 1 and 2.
4. Interference Test
4.1 Anticoagulants that come into contact with the sample (EDTA, sodium citrate, sodium heparin, sodium oxalate, and double oxalate) do not significantly interfere with the assay results of this product.
4.2 Endogenous substances—bilirubin, hemoglobin, and triglycerides—do not significantly interfere with the assay results of this product.
4.3 Fibrinogen does not significantly interfere with the assay results of this product; therefore, human serum or plasma samples may be used for testing.
[Precautions]
1. This product is intended for in vitro diagnostic use only and is for single-use.
2. The serum or plasma used to prepare the negative, positive, and critical controls for this product have been tested and found negative for HBsAg, HCV antibodies, Treponema pallidum antibodies, and HIV antibodies; furthermore, all other components included in the kit are non‑infectious. However, since it is impossible to guarantee the absence of all potential infectious agents in each component, this product should be treated as a potentially infectious material, and all personnel handling the kit must follow standard laboratory procedures.
3. All clinical specimens shall be treated as infectious materials.
4. Samples awaiting testing and other potentially infectious materials shall be disinfected after testing.
5. Take care to avoid direct contact between the reagents or samples and skin or mucous membranes. The chromogenic solution contains TMB, and the stop solution contains sulfuric acid. Reagents containing TMB may trigger unintended reactions during the assay, while those containing sulfuric acid are corrosive. If these liquids come into contact with the skin or eyes, rinse thoroughly with water immediately.
[Explanation of the Logo]
Packaging label
The logo
Meaning of the label: Temperature limits; In vitro diagnostic medical device; Refer to the instructions for use; Do not reuse.

[References]
[1] Griffiths PD. Molecular biology and immunology of cytomegalovirus. Biochem J, 1978, 241:313.
[2] Infection and Gastroenterology Group of the Chinese Society of Pediatrics, Editorial Board of the Chinese Journal of Pediatrics. Proceedings of the National Symposium on Cytomegalovirus Infection in Children. Chinese Journal of Pediatrics, 1995, 33(1):7.
[3] Xu Guilin, Chen Jiahua, Zhang Su, et al. Analysis of cytomegalovirus infection in 199 parturients and newborns. Chinese Journal of Obstetrics and Gynecology, 1989, 24(3):130.
[4] Surresh B. Boppana, Robert F. Pass, Willian J. Britt. Virus-specific antibody responses in mothers and their infants cytomegalovirus infection. The Journal Infection Diseases, 1993,167(1):72.
[5] Stagno S. In: Remington JS, Klein JO editors. Infectious diseases of the fetus and newborn infant[J]. Philadelphia: WB Saunders Co., 1995, 312-353.
[Basic Information]
Registrant/Manufacturer Name: Zhuhai Special Economic Zone Haitai Biopharmaceutical Co., Ltd.
Address: No. 18, Innovation Road No. 4, Gangwan Avenue, Tangjiawan Town, Zhuhai City Postal Code: 519085
Contact Information: Telephone: 0756-3890858 Fax: 0756-3890848
Name of After-Sales Service Provider: Zhuhai Special Economic Zone Haitai Biopharmaceutical Co., Ltd.
Contact Information: Telephone: 0756-3890858 Fax: 0756-3890848
Production Address: No. 18, Innovation Road 4, Gangwan Avenue, Tangjiawan Town, Zhuhai City Postal Code: 519085
Production License No.: Yue Food and Drug Administration Medical Device Production License No. 20040941
[Medical Device Registration Certificate Number/Product Technical Requirements Number] National Medical Device Registration No. 20173400137
[Date of Approval and Amendment of the Instruction Manual] January 23, 2017