Because multiple laboratory tests are used in the diagnosis and management of this disease, the quality of the scientific evidence supporting the use of these assays varies.  Therefore, an expert committee drafted evidence-based recommendations for the use of laboratory analysis in patients with DM.  An external panel of experts (DB Sacks, DE Bruns, DE Goldstein, NK Maclaren, JM McDonald and M Parrott) reviewed a draft of the guidelines, which were modified in response to the reviewers’ suggestions, and other steps were taken to gain a consensus of expert opinions.  The guidelines, as published in Clinical Chemistry, consist of an Executive Summary of one page providing specific recommendations based on data published or expert consensus.  Several analyses are of minimal clinical value at the present time and measurement of them is not recommended.  The entire article is 42 pages. Those clinicians treating diabetics should at least scan the article and closely scrutinize the Executive Summary.

Highlignts of the Executive Summary are now presented:

Glucose should be measured in an accredited laboratory to establish the diagnosis of DM and to screen high-risk individuals.  Blood should be drawn after an overnight fast.  Glucose should be measured in plasma.  If plasma cannot be separated from cells within 60 minutes, a tube with glycolytic inhibitor should be used.  On the basis of biological variation, glucose analysis should have analytical imprecision less than 3.3%, bias less than 2.5%, and total error less than 7.9%.

The OGTT is not recommended for the routine diagnosis of type 1 or 2 DM.  The key limitation of the OGTT is its poor reproducibility. It is recommended for establishing the diagnosis of gestational DM.

Because of the imprecision and variability among glucose meters, they should not be used to diagnose DM and have limited value in screening.  Noninvasive glucose analyses cannot be recommended at present as replacements for plasma glucose or measurements by an accredited laboratory.  Glycated hemoglobin (GH_B) should be measured at least biannually in all patients with DM. US laboratories should use GH_B assays certified by the National GH Standardization Program (NGSP) as traceable to the DCCT reference.  GH_B levels should be maintained at <7% and the treatment regimen should be reevaluated if GH_B is >8% as measured by NGSP - certified methods.

Routine measurement of genetic markers is not recommended for the diagnosis or management of patients with DM.  Likewise, autoimmune markers lack specificity and are not recommended for routine diagnosis or screening of DM.

An annual search for micro albuminuria should be performed on patients without clinical proteinuria.  To be useful, semiquantitative or quantitative screening tests must be shown to be positive in >95% of patients with micro albuminuria.  Positive results must be confirmed by quantitative testing in an accredited laboratory.

All adults with DM should receive annual lipid profiles.

Sacks DB, et al.  Clinical Chemistry 2002;48:3,436-472.

Editor’s Comment: This is only the very essential infrastructure of the Executive Summary.  The article is endowed with significant substance.

 

Robert M. Blizzard, MD