Semi-Automated 3-Part Blood Cell Counter

What is the Semi-Automated 3-Part Blood Cell Counter?

A semi-automated 3-part blood cell counter requires the operator to present each diluted sample to the aspiration probe, then measures it automatically and prints a three-part count. It costs less than a fully automatic analyzer and is suited to very low workloads, mobile clinics and teaching laboratories.

Overview

In this configuration the operator pipettes a measured volume of whole blood into a predilution tube containing diluent, mixes it, and presents the tube to the probe. The instrument performs dilution, lysis, counting and calculation automatically, then displays and prints the result. Because samples are handled individually, throughput is typically 20 to 40 samples per hour and operator technique strongly influences precision, so training and written procedures matter. The platform usually has a smaller parameter set, often 18 to 22 reported parameters, may require manual hemoglobin blanking, and stores fewer records. Advantages are the low purchase price, minimal reagent consumption, small footprint, and the ability to work without an autoloader, which suits outreach clinics with intermittent power and low daily demand.

How does it work?

A 3-part analyzer aspirates a small volume of anticoagulated whole blood, then splits it into separate channels for dilution and measurement. Red cells and platelets are counted in an isotonic diluent by the Coulter principle, in which each cell passing a small aperture displaces conductive electrolyte and creates a voltage pulse proportional to cell volume. White cells are counted in a second channel where a lysing reagent destroys red cell membranes while leaving white cells intact for sizing. The analyzer sorts white cells into three populations using two software thresholds on the size histogram: lymphocytes, a mixed population of monocytes, eosinophils and basophils, and granulocytes. Hemoglobin is released by lysis and measured photometrically at about 540 nm after conversion to a stable chromogen. Software computes indices such as MCV, MCH and MCHC, applies quality control rules, and stores or transmits the report.

What are the key features?

• Manual presentation of prediluted samples to the aspiration probe
• Automatic dilution, lysis, counting and calculation after aspiration
• Compact footprint suitable for mobile or outreach clinics
• Low reagent consumption per test and simple fluidics
• Built-in thermal printer for immediate result records
• Battery option available in some models for field use

What are the technical specifications?

A typical semi-automated 3-part blood cell counter configuration offers throughput of 20–40 samples/h, reportable parameters of 18–22 parameters with three-part differential, sample volume of 20 µL whole blood in 0.5 mL diluent, WBC linear range of 0.5–99.9 ×10⁹/L, calibration of Manual entry of calibrator values and display of LCD with alphanumeric keypad. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Semi-Automated 3-Part Blood Cell Counter is used in low-volume clinic blood counts, mobile and outreach health screening, teaching laboratory demonstrations and veterinary practice blood counts. Across the wider 3-Part Analyzers class, laboratories also deploy it for routine complete blood counts in community clinics, anemia and infection screening and pre-operative and antenatal blood counts.

Which standards and certifications apply?

Relevant standards and methods include ISO 15189, CLSI H26-A2, CLSI H20-A2, CLSI EP05, IEC 61010-1 and IEC 61010-2-101. Certification candidates for this model are CE, ISO 13485 manufacturing and NMPA class II registration; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the analyzer on a stable, level bench away from direct sunlight, strong vibration and large electrical motors, with a grounded outlet and a supply of clean, low-particulate water if the instrument needs it. Perform installation verification with the manufacturer or distributor, including background counts, precision, carryover and linearity checks with fresh or stabilized blood. Run two or three levels of quality control at the start of each working day and after reagent changes. Daily cleaning of the aspiration probe, weekly cleaning of the apertures and periodic replacement of pump tubing, seals and the peristaltic pump keep results stable. Treat all blood samples, waste and control material as potentially infectious and follow local biosafety rules for decontamination and disposal.

How do I select the right Semi-Automated 3-Part Blood Cell Counter?

Choose this variant when daily demand is below about fifty counts, when mains power or bench space is limited, or when the lowest purchase price matters more than walkaway operation. In the RFQ confirm the predilution ratio and tube format, whether hemoglobin requires manual blanking, the pH and stability requirements of the diluent, and the availability of the calibrator and control material. Operator training and a written pipetting procedure are essential.

How does it compare with other 3-Part Analyzers variants?

Choose a 3-part analyzer when the clinicians served mainly need total counts, hemoglobin and a basic differential, and when the daily workload is low enough that a 5-part flow cytometry channel would not be used. Compare variants by throughput in samples per hour, minimum aspiration volume for capillary sampling, whether the reagent system is open or proprietary, and the quality of the histogram display. Confirm autoloader capacity if more than fifty samples arrive in a batch, check barcode and LIS connectivity, and review the calibration and control materials offered. Ask about the expected life of the shear valve and pump tubing, because these parts dominate maintenance cost, and about local service response time for a clinic without an in-house engineer.