Sysmex XN-L blood analyzer maintenance and troubleshooting

Sysmex XN-L blood analyzer maintenance and troubleshooting

In clinical laboratories, automatic blood analyzers are responsible for high-frequency and continuous testing tasks. The Sysmex XN-L series includes three models: XN-530, XN-430, and XN-330. It is an automated blood analyzer for in vitro diagnostic purposes, mainly used for blood cell analysis of human blood or quality control blood in clinical laboratories. This series uses impedance spectroscopy, semiconductor laser flow cytometry, fluorescence labeling, and SLS hemoglobin method to quantify, identify, and analyze the proportion of tangible components such as red blood cells, white blood cells, and platelets in blood. For laboratory engineers, understanding equipment structure, specification boundaries, reagent systems, service data, and common fault logic is key to ensuring stable instrument operation, reducing downtime, and improving result reliability.

System composition and model differences

The three models in the XN-L series have differences in sampling methods. XN-530 belongs to the sampler analysis type, equipped with closed tube sampling, automatic sampling, barcode reading, and independent display; XN-430 belongs to closed tube analysis type; XN-330 belongs to the open analysis type. All three models cover WDF, RBC/PLT, and HGB channels, and support whole blood mode and pre dilution mode. In whole blood mode, the throughput of CBC and CBC+SIFF is approximately 60 samples per hour; Similar levels can also be achieved in pre dilution mode. The typical sample size for whole blood mode is 25 μ L, while for pre dilution mode it is 70 μ L. The pre dilution mode cannot analyze parameters such as MicroR and MacroR, which requires special attention when selecting methods.

In terms of report parameters, WDF channel can provide WBC、NEUT#、LYMPH#、MONO#、EO#、BASO#、NEUT%、LYMPH%、MONO%、EO%、BASO%、IG#、IG%  Wait. RBC/PLT channels provide RBC、HCT、MCV、MCH、MCHC、PLT、RDW-SD、RDW-CV、MicroR、MacroR、PDW、MPV、P-LCR、PCT。 The HGB channel provides hemoglobin results. Some parameters are calculated by formulas or distributions, such as MCV, MCH, MCHC, RDW-CV, MPV, etc., and cannot be simply regarded as independent measurement channels during maintenance.

Safety and installation points

Blood analyzers involve various risks such as biological samples, reagents, waste liquids, electrical and laser hazards. Protective gloves, masks, goggles, and lab coats must be worn during operation and maintenance. After completing the operation, hands should be washed with disinfectant. All surfaces of the instrument that may come into contact with the sample, sampling tube racks, waste liquid outlets, sample tube racks, etc. should be considered as potential infection risk areas. The waste liquid pipe must be connected to a dedicated waste liquid tank or facility waste liquid system, and the connection must be regularly checked for firmness to avoid waste liquid leakage. If the skin or eyes accidentally come into contact with potential infections, they should be immediately rinsed with plenty of water and cleaned and decontaminated according to laboratory regulations.

In terms of electrical safety, the instrument must be connected to a power socket that meets the requirements of the nameplate and reliably grounded. Power cables must not be placed with heavy objects or forcefully pulled. When abnormal odors or smoke appear, immediately turn off the main switch and unplug the power cord, and contact a service representative. The installation location should avoid water splashing, high temperature, high humidity, dust, direct sunlight, vibration, and strong electromagnetic interference. It is recommended to control the ambient temperature between 15 and 35 ℃, relative humidity between 20% and 85%, and atmospheric pressure between 70 and 106 kPa. Leave at least 30 cm gap on the back of the instrument for heat dissipation and maintenance. The height of the reagent container should not exceed 1 meter above and below the bottom of the analyzer, and should not be placed on the top of the instrument.

XN-530 is equipped with a display and is usually installed on the left side of the analyzer. In terms of instrument weight, XN-530 weighs approximately 53 kg, while XN-430 and XN-330 weigh approximately 35 kg. Before installation, it is necessary to confirm the load-bearing capacity of the table or floor. The power specifications are 100 to 240 V AC, 50/60 Hz, with a power consumption of approximately 250 VA for XN-530 and 235 VA for XN-430/XN-330. The instrument complies with Class I protection and IEC61010 safety standards, and the laser is Class I. In terms of electromagnetic compatibility, it complies with IEC61326-2-6 and belongs to Class A equipment. It may cause radio interference in residential environments and corresponding measures need to be taken.

Performance specifications and result boundaries

The XN-L series provides blank limits, detection limits, and quantification limits in performance validation. In whole blood mode, the LoB, LoD, and LoQ of WBC are approximately 0.00, 0.01, and 0.03 × 10 ³/μ L, respectively; RBC values are 0.00, 0.00, 0.01 × 10 ⁶/μ L; HGB is 0.0, 0.0, 0.1 g/dL; PLT is 0, 1, 2 × 10 ³/μ L; HCT is 0.0, 0.0, 0.1%. In pre dilution mode, the LoQ of WBC is approximately 0.04 × 10 ³/μ L, and the LoQ of HGB is 0.2 g/dL. In terms of linear range, WBC is allowed to deviate by ± 3% or ± 0.30 within 0.00 to 100.00 × 10 ³/μ L; Allow ± 6% within 100.01 to 310.00 × 10 ³/μ L; Allow ± 11% within 310.01 to 440.00 × 10 ³/μ L. RBC, HGB, HCT, PLT, etc. also have corresponding piecewise linear requirements.

In terms of precision, the repeatability CV of WBC in whole blood mode is not greater than 3.0%, RBC is not greater than 1.5%, HGB is not greater than 1.5%, HCT is not greater than 1.5%, and PLT is not greater than 4.0%. In pre dilution mode, the corresponding CV will be relaxed, such as WBC not exceeding 5.0%, RBC not exceeding 4.5%, and PLT not exceeding 12.0%. In terms of carrying pollution, WBC, RBC, HGB, HCT, PLT usually require no more than 1.0%, and white blood cell classification items generally do not exceed 2.0% or specific absolute values. The stability of the sample after collection is affected by temperature. WBC, RBC, and HGB can remain stable for about 72 hours at 18 to 26 ℃, HCT for about 8 hours, and PLT for about 48 hours; Under the conditions of 2 to 8 ℃, some parameters have different stabilization times. Before testing, it is necessary to restore room temperature and mix thoroughly.

In terms of software data storage capacity, it can store approximately 100000 samples, 10000 patient information, 200 wards, 200 doctor names, 2000 analysis registration records, 20 calibration logs for each analyzer, 99 QC files for each analyzer, 300 image points per file, 5000 reagent replacement logs, and 5000 maintenance logs. Quality control supports L-J control chart, approximately 300 points x 96 files, and X-barM control chart, 300 points x 3 files.

Reagents, consumables, and calibration systems

The XN-L series uses a designated reagent system. CELLPACK DCL is a diluent and sheath containing sodium chloride, Tris buffer EDTA-2K， Store at a temperature of 2 to 35 ℃ for 60 days after opening the bottle. CELLPACK DST is a concentrated reagent that needs to be connected to the designated reagent preparation device of Sysmex, stored at 15 to 30 ℃, and opened for 60 days. SULFULYSER is used for hemoglobin measurement, containing sodium dodecyl sulfate, stored at 1 to 30 ℃, and opened for 60 days. Lysercell WDF is used for hemolysis and leukocyte treatment, 90 days after opening the bottle. Fluorocell WDF is a fluorescent dye containing polyacetylene pigment, methanol, and ethylene glycol. It should be stored in the dark at 2 to 35 ℃ and opened for 90 days. CELLCLEAN AUTO is a strong alkaline cleaning solution containing sodium hypochlorite, used for pipeline cleaning and stored at 1 to 30 ℃.

Both the quality control material XN-L CHECK and the calibration material XN CAL need to be refrigerated at 2 to 8 ℃ in the dark. Use within 15 days after opening XN-L CHECK and within 4 hours after opening XN CAL. The calibration items cover WBC, RBC, HGB, HCT, and PLT. The quality control barcode usually uses CODE128, which is a fixed string of "QC -" followed by an 8-digit batch number and a 1-digit checksum. If barcode reading fails, the system may automatically assign a sample number starting with ERR; QC samples, background checks, precision checks, and calibration samples also have specific prefixes. Daily use should avoid using expired reagents, repeatedly connecting opened bottles of reagents, and using non specified sample tubes or sampling adapters. A specialized adapter is required for the 15 mm sample tube. The metal parts of the RBT micro collection tube and the conventional sample tube on the sampler are positioned differently, and incorrect installation may result in sampling failure or sample drop.

Common faults and troubleshooting strategies

1. Sampling and barcode anomalies. If barcode reading fails, first check the label position. The XN-530 barcode label should be affixed within the designated area, and the barcode strip should be horizontal without excessive attachment, wrinkling, exceeding the bottom of the tube, or using a reusable cap. Check if the barcode type is within the supported range, such as ITF, CODABAR/NW7, CODE39, JAN/EAN/UPC, ISBT128, CODE128. If using a checksum, it should be confirmed that the setting is correct. The metal parts of the sampling adapter must be installed according to the type of sample tube and cannot be disassembled or reinstalled at will, otherwise it may become loose due to the expansion of screw holes.

2. Hole blockage, bubbles, and sampling noise. In the service data, the RBC/PLT page can view sampling data, particle counts of RBC and PLT, differences between maximum and minimum values, Clog and Bubble values. If the hole is blocked or the bubble value is abnormal, the cleaning procedure should be performed, using CELLCLEAN AUTO to clean the pipeline. Avoid generating bubbles during reagent connection, as bubbles can cause abnormal analysis. If the reagent is contaminated, turbid, or discolored, it should be replaced. When maintaining areas such as the RBC detector cover, air pump unit, and pneumatic capture chamber, power should be turned off and attention should be paid to the high temperature on the surface of the air pump.

3. Abnormal results and interference. Pseudo low WBC can be seen in white blood cell aggregation; Pseudo elevated levels can be seen in platelet aggregation, hemolysis, nucleated red blood cells, red blood cell aggregation, cold agglutinin, chyle, cold protein, cold globulin, fibrin, giant platelets, etc. Pseudo low RBC can be seen in red blood cell aggregation, small red blood cells, and red blood cell debris; Pseudo elevated levels can be seen in leukocytosis greater than 100000/μ L and giant platelets. Pseudo elevated HGB can be seen in significantly increased white blood cells, lipid levels, and abnormal proteins. Pseudo low HCT can be seen in cold agglutination, small red blood cells, and red blood cell fragments; Pseudo high can be seen in leukocytosis, severe diabetes, uremia, spherocytosis. Pseudo low PLT can be seen in platelet aggregation, pseudo thrombocytopenia, and giant platelets; Pseudo elevated levels can be seen in small red blood cells, red blood cell fragments, white blood cell fragments, cold proteins, and cold globulins. Research on interfering substances shows that bilirubin C, bilirubin F, hemolysis, fat emulsion, and chyle have concentration thresholds that affect WBC, RBC, HGB, HCT, and PLT. If the threshold is exceeded, they should be treated as interference.

4. Hardware and service data anomalies. HARDWARE service data can view unit counts, ambient temperature, pressure, laser oscillation time, suction sensors, RBC/HGB discharge sensors, and more. If the temperature, pressure, or laser current deviates, it is necessary to investigate in conjunction with the instrument status. WDF service data WDF-X、WDF-Y、NE-SSC、NE-SFL、WDF-WX、WDF-WY、LY-X、LY-Y、WBC-D、TNC-D、DLT-WBCD、iRBC-WDF#、Cell 1、Cell 2、LD driver  It can be used to determine the classification of white blood cells and the status of fluorescence signals. The ADJUSTMENT page is used for sensitivity adjustment, including WDF-X/Y/Z, LY-X/Z, etc. Research parameters such as TNC、WBC-C、TNC-C、WBC-D、WBC-D&、NRBC#、NRBC%、NEUT#&、LYMP#&、HFLC#、HFLC%、NE-SSC、NE-SFL、NE-FSC、LY-X、LY-Y、LY-Z、MO-X、MO-Y、MO-Z  Waiting, usually displayed on a gray background, cannot be used for patient diagnosis, only for technical observation and method research.

5. Waste liquid, reagents, and gas pathways. The waste liquid outlet, waste liquid full sensor, RU-20 supply tank sensor, anti-static connector, etc. need to be kept connected. If the RU-20 or waste liquid sensor is not connected, an anti-static connector should be installed and cannot be removed at will. The pneumatic unit is used to provide positive and negative pressure, and the exhaust port must not be blocked. When replacing the fuse, the specified specification should be used, such as a 250V 10A delay fuse. Do not repeatedly switch the main power supply quickly to avoid overloading the fuse.

Maintenance, decontamination, and disposal

Daily maintenance should clean the outer surface of the instrument at the end of each day's work. Use a one-way cloth dipped in a suitable cleaning solution to prevent liquid from entering the interior of the instrument. If potential infectious contamination occurs, immediate decontamination should be carried out. Before repair or maintenance, the power should be turned off and the power cord should be unplugged. The internal cleaning of the instrument can only be performed by service technicians. Wear personal protective equipment during cleaning, wash hands with disinfectant first, and then wash with soap. The treatment of waste liquid must comply with local regulations. Waste liquid may contain hazardous substances, and the decision on discharge should be made by the local water department. When the instrument is scrapped, it should not be disposed of through the public recycling system due to the potential risk of infection. It is recommended to incinerate the contaminated parts and contact the service representative for disposal guidance.

The laser unit is located inside the instrument and is protected by a shielding box. Unauthorized personnel are not allowed to touch it. Use only Sysmex authorized tools for maintenance. Do not install non pre installed software, do not run other software, and check for viruses before using USB storage devices. The surface of the instrument, sample tube holder, sampling adapter, waste liquid outlet, etc. should be considered as biological risk areas.

Calibration and quality control recommendations

Calibration should be done using XN CAL within 4 hours after opening the bottle. Quality control should use XN-L CHECK, refrigerated at 2 to 8 ℃, and used within 15 days after opening the bottle. Quality control files, calibration logs, reagent replacement logs, and maintenance logs should be backed up regularly. If the quality control results exceed the target value range, the reagent expiration date, bottle opening stability, sample mixing, pipeline cleaning, calibration status, and temperature control environment should be checked. For low value samples, attention should be paid to carrying pollution effects; For high-value samples, attention should be paid to the selection of linear upper limit and dilution mode. The pre dilution mode is suitable for trace samples, but its precision and linearity requirements are different from those of the whole blood mode. When interpreting the report, it is necessary to combine methodology.