Prostate Cancer Screening
Newborn Screening
The Thromboelastogram
Community-acquired MRSA
Diagnostic Utility of Skin Biopsy
Diagnosis of Sepsis
Osteoporosis in Men
Oral Anticoagulant Therapy
Patient with Allergy
Cytology
Role of Vancomycin
Estimated average glucose
Fungitell Option 2
Evolving role of Troponins
Aspirin Resistance
Tumor Markers
Sentinel Lymph Node Biopsy
Swine Influenza
Syphillis
Hereditary Haemochromatosis
Haematological Changes in HIV
Influence of HIV
Drug induced liver injury
Alcohol Abuse
HPV testing in woman
Intravenous immunoglobulins
Death certification
Breat Cancer Month
Therapeutic Plasma Exchange
Bedroom Zoonoses

Estimated Average Glucose

---

Dr Helene Rossouw - MBChB MMed Path Chemical Pathologist

 

PATHCHAT NO 12: What is the estimated average glucose?

The estimated average glucose (eAG) is calculated from the glycated haemoglobin parameter, HbA1c, and reflects an average capillary (finger prick) glucose equivalent for the past 2-3 months. The estimated average glucose value should only be used in the follow up of patients with diabetes mellitus. It is not intended for screening or diagnostic purposes.

Why the need for eAG?

Implementing this parameter assists the clinician to better clarify to patients the concept of HbA1c (patients may tend to think that a 1% change in HbA1c is not significant because of their frame of reference as to what a % means) as an indirect measure of the average glucose over the past 2-3 months. Patients can thus more easily relate to the estimated glucose value, because this value is a capillary value and similar to the values obtained from finger prick methods that the patients are using. They then would be more likely to take responsibility for their monitoring of their diabetic condition. It should be borne in mind that this is a calculated average glucose value, reflecting continuously occurring fluctuations, and might therefore differ from individual glucose readings on the patients' glucometers as well as from laboratory determined random glucose results. This should be clearly explained to the patients during follow ups.

How was the calculation derived?

The calculation originates from the ADAG (A1c-Derived Average Glucose) study. The advantages of this study compared to previous studies are:

This study examined the relationship between average glucose and HbA1c values across a wide spectrum of HbA1c values (5-13%).

The number of subjects was more than studied before (507 subjects).

Subjects without diabetes (80), with type 1 DM (268) and type 2 DM (159) were enrolled in sufficient numbers to conclude that the relationship between the average glucose and HbA1c was consistent between these subgroups.

The number of glucose measurements was far greater than obtained in nearly all previous studies, with ~ 2700 glucose measurements in each participant.

The HbA1c level obtained at the end of a 3 month period was compared to the average glucose levels during the previous 3 months.

 

Read the full article here.