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Cyanide-Free Lyse (Reagent for Erythrocyte Lysis): LC-660, LC-667, LC-661

Lyse reagents are essential for destroying red blood cell membranes to enable white blood cell counting and hemoglobin measurement. Conventional methods often use the Cyanmethemoglobin method, which involves bonding cyanide to heme to stabilize it. The Microsemi series employs a cyanide-free lyse reagent, enhancing user friendliness and reducing environmental impact.

While cyanide-free methods can lead to less stable hemoglobin, the Microsemi series addresses this by analyzing absorption wavelengths and selecting ranges with minimal variance. A preheating diluent tank further compensates for temperature effects, ensuring precision comparable to or exceeding conventional methods.

Onboard Use of CRP Reagent: LC-667

Modern instruments require not only accurate measurements but also ease of operation and maintenance. The LC-667 utilizes an all-in-one CRP Unit 50 reagent container (Figure 2b), a significant improvement over the separate containers used in the LC-178CRP (Figure 2a).

To further enhance convenience, HORIBA developed a system for onboard reagent use, allowing reagents to remain in the instrument even after shutdown. This involved creating stable reagents and a reagent cooling unit unaffected by ambient temperature. Investigations into reagent container opening diameter (7mm) and sealing caps ensured reagent stability, minimizing concentration variances for at least two months under various conditions, thereby reducing customer effort.

Figure 2: CRP Measuring Reagents: (a) Buloimmukit CRP, (b) CRP Unit 50.

CRP Reagent Factor: LC-667

The LC-667 uses a latex immunoturbidimetric method, where reaction solution turbidity correlates with CRP concentration. Due to lot-specific reagent reactivity, calibration curves are necessary for each lot.

Unlike larger laboratory instruments that require frequent recalibration with calibrators (high accuracy but high reagent consumption), the LC-667 allows a calibration curve to be set for each lot, usable for approximately 100 measurements or two months. This is more practical for general practitioners.

To simplify input and improve accuracy, HORIBA introduced the Magic Number Table Calibration Curve Input System (Figure 3). This system stores reagent parameters in a table and uses single-digit numbers for input. For instance, five 3-digit parameters (15 characters) in a conventional system are reduced to five single-digit characters. The LC-667 uses a 10-digit number for complex calibration curves, enhancing both accuracy and ease of use.

Figure 3: Magic Number Table Calibration Curve Input System. This diagram illustrates the concept of simplifying reagent factor input by using a table and single-digit numbers, leading to higher accuracy and user-friendliness.

Piercing Probe: LC-661

The LC-661 features a cap piercing probe that penetrates vacuum sample tube caps to aspirate blood, eliminating manual opening and reducing infection risks. This function, also found on larger HORIBA analyzers, is increasingly important for general practitioners.

The LC-661's probe is a single unit that acts as both a piercing needle and a sampling probe, unlike older systems with separate components. Its smaller diameter and sharp end minimize cap damage and rubber residue. A key feature is the integrated pressure release outlet, which equalizes pressure within the vacuum sample tube before aspiration. This prevents variations in aspirated sample volume caused by internal tube pressure changes (positive or negative) due to temperature or sample volume differences. The release outlet is connected to a waste line, safely managing any potential blood spatters.

Figure 4: Piercing Probe Structure. This diagram shows a cross-section of the piercing probe, highlighting the blood sampling inlet and the pressure release outlet.

Maintenance Information Recording Function: LC-660, LC-667, LC-661

Traditionally, instrument issue reporting involved a multi-step process with potential delays and data inaccuracies. The Microsemi series streamlines this by recording measurement results and maintenance information directly on the instrument. Users can download this data to a flash card or transmit it via the Internet.

HORIBA's maintenance support system (Figure 5) receives this data, enabling rapid analysis of instrument status, problem diagnosis, and timely technical advice. The recorded information includes settings, operating history, error logs, and real-time status data.

An example illustrates the system's utility: a measurement variance was traced to low temperatures slowing the hemolytic reaction. By analyzing the maintenance data, the issue was identified, and the customer was advised to improve the installation environment, resolving the problem.

Figure 5: HORIBA Maintenance Support System. This screenshot displays the interface of the maintenance support system, showing various data categories available for analysis, including measurement data, device history, and error logs. (Note: The interface includes Japanese text.)