The Afinion HbA1c assay is a widely used point-of-care test for measuring glycated haemoglobin (HbA1c) in diabetes management across NHS primary care and community settings. A common practical question for healthcare professionals is: what is the sample size for the Afinion HbA1c assay? The test requires just 1.5 microlitres (µL) of whole blood, making it suitable for fingerprick capillary sampling. This article covers specimen requirements, how the assay works, its accuracy and clinical validation, governance requirements for NHS use, and relevant NICE and MHRA guidance on HbA1c monitoring.

How the Afinion HbA1c Assay Works

The Afinion HbA1c assay uses boronate affinity-based separation on the Afinion 2 analyser to measure HbA1c from a small blood sample, delivering results in approximately three minutes. It is NGSP certified and aligned with the IFCC standardisation framework used in UK laboratories.

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The Afinion HbA1c assay is a point-of-care (POC) diagnostic test designed to measure glycated haemoglobin (HbA1c) levels from a small capillary or venous blood sample. It is manufactured by Abbott (formerly Alere) and operates on the Afinion 2 analyser platform, used in primary care, diabetes clinics, and community health settings across the UK.

The assay uses a boronate affinity-based separation method to quantify HbA1c from total haemoglobin. Glycated haemoglobin binds selectively to boronic acid ligands within the test cartridge, allowing the analyser to calculate the proportion of haemoglobin that has been glycated. The method is aligned with the International Federation of Clinical Chemistry (IFCC) standardisation framework, which underpins HbA1c reporting in the UK, and the assay is listed on the National Glycohemoglobin Standardization Program (NGSP) certified methods register.

Results are typically available in approximately three minutes of sample insertion, according to the Abbott Afinion HbA1c Instructions for Use (IFU). This rapid turnaround supports clinical consultations where timely decision-making is needed, such as reviewing diabetes management or investigating possible hyperglycaemia. The system is designed to be operated by trained healthcare professionals without specialist laboratory infrastructure.

Healthcare professionals should always refer to the current Abbott Afinion 2 HbA1c package insert for the most up-to-date technical specifications, as these may be revised following regulatory review.

Sample Size and Specimen Requirements for the Afinion HbA1c Test

The Afinion HbA1c assay requires 1.5 µL of whole blood, collected via fingerprick capillary sampling or EDTA venous blood. Underfilling the capillary tube may produce an invalid result, and haemolysed or clotted samples should be discarded.

According to the Abbott Afinion HbA1c Instructions for Use, the sample volume required for the assay is 1.5 microlitres (µL) of whole blood. This small volume makes the test well suited to fingerprick capillary sampling, which is particularly practical for patients who find venepuncture distressing, including children, elderly patients, or those with difficult venous access.

The specimen may be collected as:

• Capillary blood obtained via a fingerprick lancet device

• Venous whole blood collected into an EDTA (ethylenediaminetetraacetic acid) anticoagulant tube

Healthcare professionals should confirm that EDTA is the only acceptable anticoagulant for venous samples, as specified in the current IFU, and should not use alternative anticoagulants unless explicitly stated therein.

Once collected, the sample is applied to the Afinion HbA1c test cartridge using the supplied capillary collection tube. Collecting the correct volume is essential — underfilling the capillary tube may produce an invalid result or an error message on the analyser.

Pre-analytical handling:

• EDTA tubes should be gently inverted several times to ensure thorough mixing before sampling.

• Refrigerated venous blood samples should be allowed to reach room temperature before testing.

• Capillary samples should ideally be tested immediately after collection.

• Venous blood stored at 2–8°C should be tested within the timeframe specified in the current IFU; users should not rely on a generic estimate and must consult the package insert for the exact validated stability period and any room-temperature limits.

Haemolysed, lipaemic, or clotted samples may affect result accuracy and should be discarded. Always refer to the current Abbott Afinion 2 HbA1c package insert for definitive specimen handling requirements.

Accuracy and Clinical Validation in UK Practice

The Afinion HbA1c assay is NGSP certified and IFCC traceable, with a total CV reported at less than 3% in manufacturer data. Conditions altering red blood cell survival — such as haemolytic anaemia or recent transfusion — can affect result accuracy.

The Afinion HbA1c assay has been evaluated in clinical validation studies assessing its performance against laboratory-based reference methods. The assay is NGSP certified and traceable to the IFCC reference method, which is the standard used in UK laboratories. Users should consult the current Abbott Afinion HbA1c IFU and independent peer-reviewed evaluations — including UK NEQAS reports where available — for detailed performance data.

Comparative studies have demonstrated correlation with high-performance liquid chromatography (HPLC) methods. The total coefficient of variation (CV), a measure of analytical precision, has been reported at less than 3% across evaluated concentration ranges in manufacturer data; however, precision may vary across the measuring range and users should refer to the IFU performance tables and independent evaluations for concentration-specific figures.

As with all HbA1c assays, certain clinical conditions can affect result reliability. These include:

• Conditions altering red blood cell (RBC) survival or turnover, such as haemolytic anaemia, iron deficiency anaemia, acute blood loss, recent erythropoietin or iron therapy, and end-stage renal disease — all of which may cause HbA1c to be falsely elevated or reduced

• Recent blood transfusion, which can dilute glycated haemoglobin and lower the measured result

• Elevated foetal haemoglobin (HbF), which may affect boronate affinity-based methods; the IFU should be consulted for specific interference thresholds

• Haemoglobin variants (e.g., HbS, HbC, HbE): boronate affinity methods are generally less susceptible to variant interference than some other methods, but the IFU should be consulted for the specific variants evaluated and any known effects

• Pregnancy, which alters RBC turnover and may affect HbA1c values

Clinicians should be aware of these potential interferences and arrange laboratory testing using an alternative validated method when such conditions are suspected. The Medicines and Healthcare products Regulatory Agency (MHRA) advises that POC devices should be used within their validated parameters and that results should always be interpreted in the context of the patient's full clinical picture.

Using Point-of-Care HbA1c Testing in NHS Settings

POC HbA1c testing in NHS settings requires staff training, internal quality control, EQA participation, and documented SOPs in line with MHRA guidance. Results must not be used as the sole basis for diagnosing diabetes; laboratory confirmation is required.

Point-of-care HbA1c testing, including the Afinion assay, is used within NHS diabetes care pathways in GP surgeries, community diabetes clinics, and pharmacies offering NHS diabetes prevention or management services. Obtaining a result within a single consultation can support patient engagement, reduce the need for return appointments, and facilitate timely clinical decisions.

It is important to note that POC HbA1c testing should not be used as the sole basis for diagnosing diabetes. Where a result is unexpected, discordant, or used in a diagnostic context, confirmation with a quality-assured laboratory HbA1c method (IFCC-aligned and NGSP certified) is required. Clinical judgement remains essential in all circumstances.

For POC testing to be used safely and effectively within NHS settings, the following governance requirements must be met:

• Staff training and competency assessment prior to independent use of the device, with records maintained

• Internal quality control (IQC) testing using manufacturer-supplied control materials at two levels (normal and abnormal), performed at the start of each working day or shift and with each new reagent lot, in line with local POCT policy

• External quality assurance (EQA) participation, such as through the UK National External Quality Assessment Service (UK NEQAS), to benchmark POC results against laboratory standards

• Device maintenance and verification in accordance with the manufacturer's schedule — note that the Afinion 2 is factory-calibrated; lot-specific calibration is managed via the test cartridge, and no user calibration is required

• Standard operating procedures (SOPs), operator identification traceability, and, where applicable, connectivity to a laboratory information system (LIS) or POCT middleware

NHS trusts and GP practices are expected to maintain a POCT governance framework, often overseen by a designated POCT coordinator or the local pathology network, in line with MHRA guidance on the management and use of IVD point-of-care test devices. Results should be documented in the patient's clinical record and, where applicable, uploaded to the relevant diabetes register or clinical system.

Suspected adverse incidents or device failures should be reported via the MHRA Yellow Card scheme to support ongoing patient safety monitoring.

NICE and MHRA Guidance on HbA1c Monitoring for Diabetes

NICE recommends HbA1c monitoring every three to six months until targets are stable, then every six months, with 48 mmol/mol (6.5%) as a key diagnostic and treatment threshold. POC HbA1c must not be used alone to confirm a new diabetes diagnosis; a quality-assured laboratory method is required.

The National Institute for Health and Care Excellence (NICE) provides guidance on the role of HbA1c in both the diagnosis and ongoing monitoring of diabetes mellitus. Key guidelines include:

• NICE guideline NG28 — Type 2 diabetes in adults: management

• NICE guideline NG17 — Type 1 diabetes in adults: diagnosis and management

• NICE guideline NG18 — Diabetes (type 1 and type 2) in children and young people

For most adults with type 2 diabetes, NICE recommends HbA1c monitoring every three to six months until the agreed target is stable, then every six months thereafter. Individual targets are agreed between the clinician and patient; a commonly referenced target is 48 mmol/mol (6.5%) for those managed by lifestyle or a single non-hypoglycaemic drug, with higher targets considered for those at risk of hypoglycaemia or with complex needs. Clinicians should refer to the relevant NICE guideline for individualised target-setting.

Diagnostic use of HbA1c

In line with WHO 2011 guidance (adopted in the UK), an HbA1c of 48 mmol/mol (6.5%) or above is diagnostic of type 2 diabetes in adults when measured on two separate occasions (or once if the person is symptomatic). A value of 42–47 mmol/mol (6.0–6.4%) indicates non-diabetic hyperglycaemia (sometimes referred to as prediabetes), warranting lifestyle intervention and regular monitoring.

However, HbA1c should not be used for diagnosis in the following circumstances, and an alternative diagnostic method (such as a fasting plasma glucose or oral glucose tolerance test) should be used instead:

• Suspected type 1 diabetes

• Children and young people

• Pregnancy or within two months postpartum

• Conditions causing altered red blood cell turnover or survival (e.g., haemolytic anaemia, haemoglobinopathies, iron deficiency, recent blood transfusion)

• Symptoms present for fewer than two months

For diagnostic purposes, HbA1c must be measured using a quality-assured laboratory method (IFCC-aligned and NGSP certified). POC HbA1c results should not be used alone to confirm a new diagnosis of diabetes; any diagnostic result should be confirmed by a laboratory test, in line with NHS England, Public Health England, and Diabetes UK guidance.

Regulatory requirements

The MHRA regulates POC devices including the Afinion analyser as in vitro diagnostic medical devices (IVDs) under UK legislation. Under current MHRA transitional arrangements, devices may hold CE marking or UKCA marking; the legal manufacturer is responsible for registering the device with the MHRA. Healthcare organisations should verify that any POC device in use holds the appropriate valid marking and is registered on the MHRA device register. Suspected adverse incidents or device failures should be reported via the MHRA Yellow Card scheme.

Frequently Asked Questions