Unopened DRSB can be stored up to the expiration date shown on the label of the beads. When beads are properly handled after opening, they are usable up to the expiration date shown. Proper handling means bottle and contents are maintained in sterile fashion, immediately closing the bottle after removing a sample, and storing the bottle at +4 to +8°C after use.
Using a new lot for retesting with Density Reference Standard Beads
Please note the following when checking the calibration of the instrument using Density Reference Standard Beads following the protocol described in the Instructions for Use: If the calculated mean Total Cell Density for the first bottle of DRSB is outside the specified range, the second bottle used to recheck the calibration must come from a different lot number The Batch type (A or B) can be the same as the one used for the first check, as long as the actual lot number, noted on the bottle label, is different.
"Name": "Protocols - Help Corner"
"Value": "Density Reference Standard Beads are used to calibrate and adjust the Cedex HiRes Analyzer.",
Preparation of the DRSB solution
Verify that the beads have been stored correctly at +2 to +8°C.
Do not freeze the beads.
Verify that the bottle was securely closed before use. – Check the weight of the unopened bottle; the correct value is on the bottle label.
Allow the beads to acclimate to +23 to +27°C prior to use.
Shake the beads using an ultrasonic bath at +23 to +27°C and at the highest available intensity for 5 minutes.
Cap should be slightly loosened but secured against falling over.
Ensure that no beads are sticking to the base or side of the bottle before use.
The DRSB solution contains SDS, which may show signs of some coagulation or crystallization at low temperatures. Allow the beads to acclimate with occasional mixing at +25°C until the coagulation or crystallization disappears. Alternatively, gently roll the DRSB bottle between the palms of the hands until the coagulation has disappeared. As long as the DRSB solution has been allowed to acclimate to +23 to +27°C, and all steps in this Instructions for Use have been carried out, any remaining coagulation or crystallization will have no effect on the performance or quality of the DRSB solution when used in a Cedex HiRes Analyzer.
"Name": "Working Solution"
"Value": "Composition of the Density Reference Standard Beads
The Density Reference Standard Beads are made of polystyrene.
Density Reference Standard Beads have a diameter of approximately 10 μm.
Obtaining Certificates of Analysis (CoA)
Download Roche Applied Science CoAs at: https://www.roche-applied-science.com/PROD_INF/index.jsp?&id=certOfAnaly
For Density Reference Standard Beads with Material Numbers 05650488001 and 05963583001: Download CoAs using the catalog number and lot number on the outer packaging of the DRSB kit packaging. Please note that numbers on the bottle are production numbers, and for internal Roche use only. For this reason, please retain the outer DRSB kit packaging for to use the appropriate numbers for downloading CoAs, and to obtain more product information.
For Density Reference Standard Beads with the Material Numbers 06422659001 and 06422667001: Download CoAs using the catalog number and lot number on the outer kit packaging or on the bottle label.
Differences between Density Reference Standard Beads and Control Beads
The Density Reference Standard Beads (DRSB) are used as an absolute check of all systems. DRSB are measured by Cedex HiRes Analyzers, allowing for a calibration and for cross-comparison of results between systems. The average from 10 replicate measurements should match the actual concentration for the DRSB listed on the bottle label (expressed as particle number/ml) to within +/- 5%, when the instructions in the package insert have been used.
DRSB should be used to determine whether the system is measuring accurately. Control Beads alone cannot be used for this purpose. Control Beads are different from the DRSB in one important way: Unlike DRSB, due to slight variations in hardware from system to system, measurement results using a single bottle of Control Beads can differ slightly when measurements are carried out with different analyzers. Therefore, Control Beads bottles that have not been used before must be calibrated with respect to the certified nominal value.
The ‘device-specific target value’ must be determined for each bottle of Control Beads and each analyzer. The device-specific target value is calculated by taking the mean of 10 measurements that have been carried out on the same analyzer for which the Control Beads will be used. The device-specific target value is used as the benchmark (100%) for the evaluation of measurements carried out with that specific bottle of Control Beads. Before determining the device-specific target value for a new bottle of Control Beads, an absolute check of the system must first be carried out using DRSB.
Using Control Beads instead of Density Reference Standard Beads to verify calibration
Control Beads cannot be used to ensure that systems are correctly calibrated. Density Reference Standard Beads (DRSB) must be used to ensure that systems are properly calibrated and that the flow factor is correctly adjusted before the device-specific target value is determined for a bottle of Control Beads and unique Cedex HiRes System.
Calibration check recommendations using Cedex Density Reference Standard Beads
The Density Reference Standard Beads (DRSBs) mimic cell flow dynamics in Cedex HiRes Analyzers. Their size and optical properties cause the Cedex HiRes Software to detect DRSBs as dead cells. Use the protocol in the Instructions for Use for DRSB to adjust Cedex HiRes Analyzers calibration (flowfactor) or to verify calibration.
There are no firm guidelines for how frequently to perform calibration checks using DRSB. Performing calibration verification ensures that the Cedex HiRes System is working to specification. Monthly calibration checks in which 10 DRSB samples are measured are a good starting point. However, each laboratory must establish their own DRSB calibration frequency based on their needs. Factors that should be considered include:
Risk analysis: Calibration testing using DRSBs is an after-the-fact check of the system. Such calibration checks confirm that the system was correctly calibrated between successful calibration checks. Such testing does not confirm whether the system will remain correctly calibrated for future measurements. Each lab must determine the acceptable risk before the next calibration check.
Laboratory and sample conditions: Dust and particles in a laboratory, and cell samples with large particles can impact Cedex HiRes System performance. Dust, large particles, and debris can enter Cedex HiRes System tubing, resulting in clogging of tubing and the flow chamber. Clogging may not always be visible in the prescan image, and may require additional cleaning. Clogging can impact system calibration. For best results, perform frequent calibration checks when cell cultures have large particles, or dust and particles are present.
"Name": "Background Information - Help Corner"
"Value": "Warming up Density Reference Standard Beads The Density Reference Standard Beads (DRSB) solution contains sodium dodecyl sulfate (SDS), which may show signs of coagulation or crystallization at low temperatures. Crystals and/or coagulation can be removed by mixing the beads at +25°C until coagulation disappears. Alternatively, the DRSB bottle can be gently rolled between the palms of hands until the coagulation has disappeared. Note when the DRSB solution reaches +23 to +27°C and all steps in the package insert have been carried out, remaining coagulation or crystallization will have no effect on the performance or quality of the DRSB solution when used in a Cedex HiRes System.
Evaporation When handled correctly, the lid is tightly closed, and the bottle is stored at +4 to +8°C immediately after use, evaporation will not be a problem. Although DRSB are stored at +4 to +80C, the bottle must be warmed to +23 to +27°C before use. Final DRSB concentration is mainly affected by improper mixing and/or sampling. DRSB are extremely sensitive to sampling errors and must be thoroughly mixed each time before a sample is removed. When the solution has been improperly mixed and a sample is removed from the top of the solution, there is a risk that the sample removed will be less concentrated. The solution left in the bottle will consequently become more concentrated, which can affect future calibration checks. The package insert included with DRSB kits provides more details about recommended mixing procedures. ",
"Name": "Troubleshooting - Help Corner"
"Value": "Designed for use with Cedex HiRes Analyzer.",
"Value": "For flow factor adjustment of the Cedex HiRes Analyzer, a minimum of two DRSB vials with different batch numbers is required (Batch A and Batch B).",