Lab Quality Results at the Point-of-Care
The A1CNow®+ system provides healthcare professionals with a fast and easy way of obtaining accurate A1C results with just a fingerstick. This innovative technology enables clinicians to communicate face-to-face with patients about their diabetes control in minutes, not days.
- Results in 5 minutes
- Small (5µL) blood sample
- Portable – use in multiple exam rooms
- Easy to use – minimal training required
- Available in multiple test count configurations
- No maintenance
- Available with IFCC (mmol/mol)
Point-of-Care Alternatives to A1C Testing
In the U.S. point-of-care test are indicated for monitoring diabetes, but not screening or diagnosis due to perceived inaccuracy. To counter this impression, we evaluated the performance of two point-of-care analyzers relative to the clinical laboratory.
The American Diabetes Association (ADA) recommends A1C testing to determine a patient’s average blood glucose control. For patients whose therapy has changed or who are not meeting glycemic goals, the A1C test should be performed quarterly. The A1C test should be performed at least two times a year in patients who are meeting treatment goals and who have stable glycemic control. Guidelines about A1C testing by the American Diabetes Association, International Diabetes Federation, and National Institute for Health and Clinical Excellence are summarized in the table below.
Guidelines for A1C testing in patients with diabetes
The goal of therapy is to achieve an A1C as close to the non-diabetic range as possible without severe hypoglycemiaC
- ADA Diabetes Care 2014; 37 (Suppl 1):S14-80
- IDF, http://www.idf.org/sites/default/files/IDF-Guideline-for-Type-2-Diabetes.pdf
Less stringent treatment goals than those noted in the chart above may be appropriate for patients with a history of severe hypoglycemia, patients with limited life expectancies, very young children or older adults, and individuals with comorbid conditions.1
- American Diabetes Association. Executive Summary: Standards of Medical Care in Diabetes-2009. Diabetes Care, 32 (S1) 2009, pp. S6-S7.
The Diabetes Control and Complications Trial (DCCT) was the pivotal trial that provided the link between A1C levels and the risk of diabetes-associated complications. The results of the DCCT shown below are considered definitive for patients with type 1 diabetes. Relative risk increased with A1C for retinopathy, nephropathy, and microalbuminuria, and the risk of retinopathy and nephropathy accelerated at the highest levels of A1C. In this study, improved glycemic control following intensive diabetes therapy delayed the onset and slowed the progression of diabetic retinopathy, nephropathy and neuropathy in patients with type 1 diabetes.1
DCCT A1C levels and the risk of complications in type 1 diabetes
Adapted from DCCT. Diabetes 1995;44:968-43.
The United Kingdom Prospective Diabetes Study (UKPDS) was a large-scale trial that investigated the effect of intensive blood glucose control versus conventional treatment in patients with type 2 diabetes, with a median follow-up of 10 years. This observational analysis of data from the UKPDS demonstrated a direct relationship between the risk of diabetic complications and glycemia over time. Each 1% absolute reduction in mean A1C levels was associated with a 37% decrease in the risk of microvascular complications and a 21% reduction in the risk of any diabetes-related complication or death.
Therefore, any improvement in A1C levels is likely to reduce the risk of diabetic complications. 2
Lowering A1C levels reduces the risk of diabetes complications in people with type 2 diabetes
UKPDS: 21% risk reduction per 1% absolute decrease in A1C levels (p<0.0001)
A1CNow+ Fingerstick Comparative Testing
(NGSP-certified method is the Tosoh A1C 2.2 Plus)
A1CNow+ Venous Comparative Testing
(NGSP-Certified method is the Tosoh A1C 2.2 Plus)
Venous blood was collected from 110 diabetic subjects, and each sample was tested on one of three different lots. Aliquots of the venous samples were also tested by the NGSP-certified method, providing comparative results. Data analysis again consisted of least squares linear regression (x = reference results), bias calculation, and Bland-Altman limits. The data are provided below.
2. Is the A1CNow+ system precise?
Precision is the quality of being repeatable in amount or performance. Precision of a test is observed when measurement of a sample has nearly the same value each time it is measured. Precision testing was done under a specialized protocol. Following this protocol, two whole blood samples, one of approximately 6.0% A1C (low), and one of approximately 9.0% A1C (high), were tested over 20 days and four runs per day, for a total of 80 assays per level. The overall imprecision (including within-day and between-day) was 3.00% CV at the low level and 4.02% CV at the high level.1
3. What is the National Glycohemoglobin Standardization Program (NGSP) certification?
The NGSP standardizes glycated hemoglobin test results so that clinical laboratory results are comparable to those reported in the Diabetes Control and Complications Trial (DCCT) where relationships to mean blood glucose and risk for vascular complications have been established. A key component of the program is the Reference Laboratory Network. The network interacts with manufacturers of glycohemoglobin methods to assist them first in standardizing their methods and then in providing comparison data for certification of traceability to the DCCT.
4. How does an A1C testing method become NGSP certified?
The NGSP certification process includes the exchange of 40 patient blood samples and a method comparison analysis. A certificate of traceability to the Diabetes Control and Complications Trial (DCCT) Reference Method is issued to any manufacturer or laboratory that successfully completes the certification process. The certificate is effective for 1 year and is specific to the reagents and instrumentation used during certification. The process consists of a 40 sample comparison with a Secondary Reference Laboratory (SRL). In order for a commercial method to be considered traceable to the Central Primary Reference Laboratory, the 95% CI of the differences between methods (test method and SRL method) must fall within the limits of ±0.75% A1C. Effective 9/1/2012, the NGSP certification requirements have been significantly tightened and 37 of 40 results must be within +/- 6% (relative) of the reference (true) value when measured in the 4-10% A1C range. The new NGSP criteria applies to methods annually certified after 9/1/2012, and will thus apply to all certified methods by 9/1/2013. Changes in NGSP criteria generally require a 1 year roll over period for currently certified methods.
5. Why do I see differences in A1C results when using multiple A1C devices?
There will always be differences between multiple test results due to normal variation, time between tests, and differences between methods. In fact, duplicate test results from the same patient will rarely match even when the test is performed using the same method at the same time. Differences can sometimes appear greater because one result could be slightly higher and the other could be slightly lower than the reference (true) value. Positive and negative biases are often present in all of the most frequently used A1C testing methods. Multiple A1C methods should not be used to evaluate a single patient or the performance of an A1C testing device because large and sometimes unacceptable inter-method differences are possible when multiple A1C testing devices are used for an individual patient.2
6. Why do I sometimes see differences in A1C results of the same blood sample when tested on the same A1C device?
There will always be differences between multiple test results due to normal variation, time between tests and differences between methods. In fact, duplicate test results from the same patient will rarely match even when the test is performed by the same method at the same time. Differences can sometimes appear greater because one result could be slightly higher and the other could be slightly lower than the reference (true) value.
7. What are hemoglobin variants?
While in most people, Hemoglobin A accounts for 95 to 98% of their hemoglobin. Some individuals have genetic variations (such as Hemoglobin S or Hemoglobin F) that could affect the accuracy of a HbA1c test.
Sickle Cell Trait and Other Hemoglobinopathies and Diabetes: Important Information for Physicians (National Diabetes Information Clearinghouse)
- Professional product insert P/N 90821B.
- Holmes, E.W. et. al. (2008). Analytic Bias among Certified Methods for the Measurement of Hemoglobin A1c. American Journal of Clinical Patholog, 129, 540-547.
PTS Diagnostics’ A1CNow®+ system is annually certified by the National Glycohemoglobin Standardization Program (NGSP).
- The purpose of the NGSP is to standardize glycated hemoglobin test results so that A1C results are comparable to those reported in the Diabetes Control and Complications Trial (DCCT) where relationships to mean blood glucose and risk for vascular complications have been established.
- In order to achieve NGSP certification, an A1C testing method must successfully complete rigorous testing requirements annually.
- A key component of the certification process is the Reference Laboratory Network. The network interacts with manufacturers of glycohemoglobin methods to assist them first in standardizing their methods and then in providing comparison data for certification of traceability to the DCCT.
- A1C test methods are awarded a ‘certificate of traceability to the DCCT reference method’ if they pass rigorous accuracy-testing criteria.1
The relationship between the National Glycohemoglobin Standardization Program (NGSP) A1C calibration (expressed as % A1C) and the International Federation of Clinical Chemistry (IFCC) network calibration (expressed as mmol/mol) has been shown to be stable and is given by the master equation: (NGSP = [0.09148 * IFCC] + 2.152). For further details and additional references, see the NGSP website at http://www.ngsp.org/.
The A1CNow+ system is NGSP certified (DCCT-traceable) and results can be converted to IFCC units with the master equation. Demonstrating IFCC traceability is a formal process during which A1C blood samples are assigned values by the IFCC network. Manufacturers use these samples to verify alignment of their assay with the IFCC network. The A1CNow+ system is now IFCC-traceable, while continuing to maintain NGSP certification (DCCT-traceable).
- National Glycohemoglobin Standardization Program webpage, http://www.ngsp.org
Maintaining A1C levels as close as possible to normal limits has been shown to lower the risk of micro- and macrovascular complications. Despite the advent of novel therapies, historically, diabetes management has failed to achieve and maintain glycemic targets. Therefore, the EASD and ADA released joint consensus guidelines to support HCPs by providing treatment algorithms for effective diabetes management.
The Guidelines and Treatment Algorithm emphasize[1,2]
- Importance of achieving and maintaining normal glycemic goals
- Initial therapy with lifestyle modifications and metformin
- Rapid addition of medication and transition to new regimens when glycemic goals are not achieved or sustained
- Early addition of insulin therapy in patients who do not meet glycemic goals.
- The guidelines acknowledge the important role of SMBG, particularly to help achieve glycemic goals with the latter two treatment regimens
Lifestyle intervention and metformin
a. Check HbA1c every month until HbA1c is <7%, and then at least every 6 months.
b. Although three oral agents can be used, initiation and intensification of insulin therapy is preferred based on effectiveness and expense.
c. See algorithm for initiation and adjustment of insulin.
Nathan D, et al. Diabetes Care 2006;29:1963–72. Reproduced with permission.
- Nathan et. al. “Management of Hyperglycemia in Type 2 Diabetes: A Consensus Algorithm for Initiation and Adjustment to Therapy”, Diabetes Care 2006, 29 (8), pp. 1963-1973.
- Inzucchi Ctal “Management of Hyperglycemia in Type 2 Diabetes: A Patient Centered Approach”, Diabetes Care 2012, 35: 1364-1379
- Nathan, DM, Kuenen, Borg, R, Zheng, H, Schoenfeld, D, Heine, RJ. “Translating the A1C Assay Into Estimated Average Glucose Values” Diabetes Care Volume 32 (8), August 2008.
- NGSP Website: http://www.ngsp.org/ifcc.asp
Although PTS Diagnostics does not currently manufacture A1CNow control solution, there are several A1C control solution options on the market that can be used with the A1CNow+ System. The following links will take users to websites where control solutions for the A1CNow+ system may be purchased:
Reference Number: Reference Numbers: NGSP Information Results Labels Proficiency Testing Control Log
What are the advantages of the A1CNow+ test by PTS Diagnostics?
A1CNow+ is fast, easy, and accurate. It provides A1C results in 5 minutes which are 99% laboratory accurate*. These A1C tests are for use in a doctor’s office. Providing real-time results outside of the laboratory, A1CNow+ is a hand-held, portable monitor which allows A1C testing in every exam room. Real-time A1C results allow for timely decisions on therapy changes when needed. The product requires no maintenance. Office staff no longer have to prepare and refrigerate lab samples. Obtaining A1C results during the patient office visit eliminates follow-up phone calls to discuss results and possible therapeutic changes. Our A1CNow® System is CLIA waived and certified by the National Glycohemoglobin Standardization Program (NGSP).
* Study results with healthcare professionals showed that the accuracy of A1CNow+ with fingerstick samples was, on average, 99%. This means that, on average, a true 7.0% A1C could read approximately 6.9% A1C. An individual A1CNow+ result may differ by as much as -1.0% A1C to +0.8% A1C from the true result. This represents the 95% confidence limits of a Bland-Altman plot.
How does the A1CNow+ test work?
The single-use test provides quantitative results from a single drop of blood. Lance the finger for an adequate drop of blood. Touch the blood drop with the tip of the blood collector. Insert the blood collector into the open end of the sampler body and shake. Insert the cartridge into the A1CNow+ monitor. Deliver the sampler body into the cartridge. Your result will display after 5 minutes. Results are 99% laboratory accurate*.
*Study results with healthcare professionals showed that the accuracy of A1CNow+ with fingerstick samples was, on average, 99%. This means that, on average, a true 7.0% A1C could read approximately 6.9% A1C. An individual A1CNow+ result may differ by as much as -1.0% A1C to +0.8% A1C from the true result. This represents the 95% confidence limits of a Bland-Altman plot.
What is the National Glycohemoglobin Standardization Program (NGSP)?
The NGSP standardizes glycated hemoglobin test results so that clinical laboratory results are comparable to those reported in the Diabetes Control and Complications Trial (DCCT) where relationships to mean blood glucose and risk for vascular complications have been established. A key component of the program is the Reference Laboratory Network. The network interacts with manufacturers of glycohemoglobin methods to assist them first in standardizing their methods and then in providing comparison data for certification of traceability to the DCCT.1
What is the Clinical Laboratory Improvements Amendment (CLIA)?
Clinical Laboratory Improvements Amendment (CLIA) is an act of Congress that established quality standards for all laboratory testing to ensure the accuracy, reliability, and timeliness of patient test results regardless of where the test was performed.2
What does CLIA waived mean?
A CLIA waived test has been reviewed by the Food & Drug Administration (FDA) and Centers for Medicare and Medicaid Services (CMS). It is defined as simple laboratory examinations and procedures that are cleared by the FDA for home use; employ methodologies that are so simple and accurate as to render the likelihood of erroneous results negligible; or pose no reasonable risk of harm to the patient if the test is performed incorrectly.3