The cobas b 221 Blood Gas and Electrolyte Analyzer from Roche Diagnostics is a fully automated analysis system, designed for accurate quantification of various important in-vitro diagnostic parameters. This system can analyze a diverse range of sample types including whole blood, serum, plasma, dialysate, and pleural fluid.

The cobas b 221 offers a broad test menu, including the following parameters:

• pH
• Blood Gases (BG): PO2, PCO2
• Electrolytes (ISE): Na+, K+, Cl-, iCa2+
• Hematocrit (Hct)
• Metabolites (MSS): Glucose, Lactate, Urea/BUN (only available on cobas b 221<6> system)
• Total Hemoglobin (tHb)
• Oxygen Saturation (SO2)
• COOX Hemoglobin Derivatives: O2Hb, HHb, COHb, MetHb
• Bilirubin (neonatal) In addition, the cobas b 221 system can also calculate derived parameters.

Advanced Measurement Principles:

• PO2: Uses the Clark measurement principle, based on the current generated by oxygen reduction.
• PCO2: Uses the Severinghouse principle, measuring the potential of pH changes in the electrode caused by CO2.
• pH, Na+, K+, Ca2+, Cl- Electrodes: Are potentiometric electrodes, using special glass or membranes containing neutral carrier/special ion exchange.
• Glucose, Lactate: Based on oxidation processes that produce H2O2, which is then determined by amperometric measurement.
• Urea: Based on the decomposition of Urea into ammonia and carbon dioxide, then the ammonium ion is determined by an ammonium ion-selective potentiometric electrode.
• COOX (Hemoglobin Derivatives and Total Bilirubin): Determined by photometric measurement based on the Lambert-Beer law.
• Hematocrit: Measures the electrical conductivity of the sample in the ISE measuring chamber.

The system has multiple configurations to meet diverse laboratory needs:

• cobas b 221<2> system: pH, PO2, PCO2, SO2, tHb, O2Hb, COHb, MetHb, HHb, Bili.
• cobas b 221<4> system: pH, PO2, PCO2, Hct, Na+, K+, iCa2+, Cl-, SO2, tHb, O2Hb, COHb, MetHb, HHb, Bili.
• cobas b 221<6> system: pH, PO2, PCO2, Hct, Na+, K+, iCa2+, Glu, Lac, Urea, Cl-, SO2, tHb, O2Hb, COHb, MetHb, HHb, Bili.

The cobas b 221 is designed with numerous superior features, ensuring safe and efficient operation:

• Optional integrated AutoQC compartment.
• Flexible sample loading support: Can measure samples from syringes (without needles), vials, and capillary tubes.
• Easy consumable management: Electrodes, solutions, fluid packs, and quality control materials are readily available. Each electrode has a specific lifespan (e.g., Cl- electrode 39 weeks, pH electrode 38 weeks, reference electrode 52 weeks).
• User-friendly design: Integrated screen/PC unit, integrated printer.
• Ensured operational safety: Complies with safety standards (ANSI Z535.6, IEC 61010-1). Provides detailed warnings and precautions regarding biological hazards, electrical shock, sharp objects, and chemicals. Requires operators to be trained by Roche and always use appropriate personal protective equipment (safety glasses, lab coat, gloves).

Key Specifications:

• Operating Environmental Conditions: Ambient temperature 15–31 °C, relative humidity 20–85% (non-condensing), air pressure 70–106 kPa.
• Physical Specifications: Width 51 cm (+20 cm AutoQC module extension + 45 cm touchscreen), height 59 cm, depth 60 cm.
• Weight: Approximately 46.2 kg (excluding washing/calibration solutions and AutoQC).
• Low Noise Level: Below 60 dB(A) under normal operating conditions.
• Connectivity: USB 3.0 port (SN > 21000).