Microvolume ESR Analyzer for Capillary Microtubes

What is the Microvolume ESR Analyzer for Capillary Microtubes?

A microvolume ESR analyzer measures the sedimentation rate in capillary tubes holding 20 to 50 microliters of blood, which makes it suitable for pediatric patients and for laboratories that need an ESR result from the same finger-stick sample as a blood count.

Overview

This variant is designed around small-bore capillary tubes and low sample volumes. Blood is drawn into the capillary by capillary action or by a pipette, one end is sealed, and the tube is placed vertically in a temperature-controlled holder. An optical head tracks the interface, and software extrapolates the one-hour value. Sample volume is often 20 to 50 microliters, and the instrument accepts capillary blood collected in a heparinized or EDTA microtube. Because the tube bore is smaller than the standard Westergren tube, the analyzer uses a validated conversion algorithm, and local verification against a reference method is essential. Throughput is lower than a batch analyzer, often 10 to 30 samples per hour, but the low sample volume and small footprint suit pediatric clinics and outpatient settings.

How does it work?

When anticoagulated blood stands in a vertical tube, red cells aggregate and settle, leaving a column of clear plasma above them. The height of that plasma column after one hour, expressed in millimeters, is the Westergren sedimentation rate. Aggregation is promoted by fibrinogen and globulins, so an elevated rate indicates an acute phase response even though the test is not specific for any diagnosis. Automated instruments reproduce this process with capillary tubes held vertically at a controlled temperature, usually 18 to 25 degrees Celsius, and track the falling interface with an array of photodiodes or an infrared sensor. Because the settling curve is nonlinear, algorithms extrapolate a one-hour value from a shorter measurement period, and the algorithms are validated against the Westergren reference method. Some instruments read standard Westergren tubes with a barcode instead of using capillary tubes.

What are the key features?

• Sample volume of 20 to 50 microliters from a finger stick
• Capillary action filling with sealed microtube handling
• Optical interface tracking with validated conversion algorithm
• Temperature-controlled tube holder for stable sedimentation
• Low throughput design for pediatric and outpatient use
• Compact bench footprint with minimal reagent consumption

What are the technical specifications?

A typical microvolume esr analyzer for capillary microtubes configuration offers throughput of 10–30 samples/h, sample volume of 20–50 µL capillary blood, measuring range of 0–120 mm/h, tube type of Heparinized or EDTA microtubes, sealed, measurement time of About 30 min with extrapolated one-hour value and temperature control of 18–25 °C controlled holder. 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 Microvolume ESR Analyzer for Capillary Microtubes is used in pediatric ESR testing, outpatient clinics with finger-stick sampling, neonatal and infant inflammation assessment and field and mobile health screening. Across the wider ESR Analyzers class, laboratories also deploy it for screening for inflammatory and infectious disease, follow-up of rheumatoid arthritis and vasculitis and monitoring of polymyalgia rheumatica and giant cell arteritis.

Which standards and certifications apply?

Relevant standards and methods include ISO 15189, ICSH ESR reference method, CLSI H02, 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 surface free of vibration, because any movement disturbs the settling interface, and keep it away from direct sunlight and heat sources so that the measuring position stays within the specified temperature range. Verify performance at installation against the Westergren reference method on at least forty samples spanning normal and elevated values, and repeat the comparison after major service. Run control material at the recommended frequency, usually daily when samples are reported, and keep the optical windows, tubes and holders clean. Use only the specified capillary or Westergren tubes, since tube bore and cleanliness affect the result, and treat all blood samples and used tubes as infectious waste.

How do I select the right Microvolume ESR Analyzer for Capillary Microtubes?

Select this variant when sample volume is the limiting factor, for example in pediatric or neonatal care, or when ESR is requested on the same finger-stick sample as a capillary blood count. In the RFQ confirm the minimum volume, the tube type supplied, the conversion algorithm validation and the availability of controls suitable for the small volume mode.

How does it compare with other ESR Analyzers variants?

Choose an ESR analyzer when the test is requested often enough that manual Westergren tubes consume unacceptable technician time, generally more than ten to twenty tests per day. Compare instruments by throughput, sample volume, tube type and the temperature control of the measuring position. Capillary photometry models accept small volumes and suit pediatric work, while instruments reading standard Westergren tubes may be preferred where the reference method must be preserved for accreditation. Check whether the analyzer needs a dedicated blood collection tube or can use an EDTA or citrate tube already collected, and whether mixing is automatic. Confirm quality control material availability, calibration or verification procedure, and biosafety features such as closed tube handling.