Comparability of HbA1c and lipids measured with dried blood spot versus venous samples: a systematic review and meta-analysis

Abstract

BackgroundLevels of haemoglobin A1c (HbA1c) and blood lipids are important determinants of risk in patients with diabetes. Standard analysis methods based upon venous blood samples can be logistically challenging in resource-poor settings where much of the diabetes epidemic is occurring. Dried blood spots (DBS) provide a simple alternative method for sample collection but the comparability of data from analyses based on DBS is not well established.MethodsWe conducted a systematic review and meta-analysis to define the association of findings for HbA1c and blood lipids for analyses based upon standard methods compared to DBS. The Cochrane, Embase and Medline databases were searched for relevant reports and summary regression lines were estimated.Results705 abstracts were found by the initial electronic search with 6 further reports identified by manual review of the full papers. 16 studies provided data for one or more outcomes of interest. There was a close agreement between the results for HbA1c assays based on venous and DBS samples (DBS = 0.9858venous + 0.3809), except for assays based upon affinity chromatography. Significant adjustment was required for assays of total cholesterol (DBS = 0.6807venous + 1.151) but results for triglycerides (DBS = 0.9557venous + 0.1427) were directly comparable.ConclusionsFor HbA1c and selected blood lipids, assays based on DBS samples are clearly associated with assays based on standard venous samples. There are, however, significant uncertainties about the nature of these associations and there is a need for standardisation of the sample collection, transportation, storage and analysis methods before the technique can be considered mainstream. This should be a research priority because better elucidation of metabolic risks in resource poor settings, where venous sampling is infeasible, will be key to addressing the global epidemic of cardiovascular diseases.

Infant cholesterol and glycated haemoglobin concentrations vary widely—Associations with breastfeeding, infant diet and maternal biomarkers

“…TC concentrations from the DBS method and venous blood samples measured by two accredited laboratories correlated strongly (Vitas and Fürst; Spearman r = .94, P < .001 for both). In a meta‐analysis based on 12 studies, a close agreement between HbA1c measured by DBS and venous blood samples was found …”

Diabetes and Cardiovascular Disease Risk in Cambodian Refugees

“…In addition, the CHS relied on analysis of dried blood spots to assess total cholesterol and HbA1c whereas the NHANES used venous blood specimens. Although a growing body of research shows evidence of good concordance between methods 22 and the dried blood spot testing is becoming widely-used in large scale, population-based survey research 40 , analysis of venous blood remains the “gold standard.” Concerns regarding reliance on dried blood spot testing in the CHS may be somewhat mitigated given that self-reports and the physical assessments for conditions not involving dried blood spot testing (i.e., hypertension) resulted in a similar pattern of findings.…”

“…DBS analysis for HbA1c has been validated against venous blood assays in several studies with venous blood scores predicting DBS scores with a high degree of accuracy. 22 A widely-used conversion formula was applied to equate DBS values to venous blood equivalent values. 23 For the CHS study, total cholesterol was measured using fluorometric assay.…”

“…24 DBS analysis for total cholesterol has been validated against venous blood assays with venous blood scores predicting DBS scores moderately well. 22 A conversion formula was used to equate DBS total cholesterol values with venous blood values. 25 Hyperlipidemia was defined by total cholesterol level ≥ 240 mg/dL.…”

Prevalence of dysglycaemia in rural Andhra Pradesh: 2005, 2010, and 2014

“…Analysis was done by immunoturbidimetry using the Randox latex agglutination inhibition assay (Randox Laboratories, Crumlin, UK). The DBS findings were minimally adjusted using a regression equation that defines the association between immunoturbidimetric analyses of HbA1c DBS samples and fasting venous samples tested using hand‐held glucose monitors . Diabetes was defined as self‐reported diabetes or HbA1c >6.5% and prediabetes as 5.7% < HbA1c ≤ 6.4%…”