Upsala J Med Sci 99: 373-376, 1994 

7.7 Reference Intervals for Sedimentation Rate 

Preben Wiggersl, Jplrgen Dalhplj2, Ole Blaabjer8, Per Hyltoft Petersen3, 

1. Department of Medicine, Haderslev Sygehus, DK-6100 Haderslev, Denmark. 
2. Department of Cardiology, Odense Uniuersity Hospital, DK-5000 Odense C, Denmark. 

3. Department of Clinical Chemistry, Odense University Hospital, DK-5000 Odense C, Denmark. 

The erythrocyte sedimentation rate (ESR) is used to monitor the activity of the acute 
phase reactants, which are raised due to inflammation or necrosis of tissues. However, 
in order to implement the ESR it is essential to investigate the variations in a healthy 
population. 

Materials and Method 

4,202 consecutive blood samples from blood donors - 2,346 males and 1,856 females - 
were investigated using Westergren’s method (2) for determination of ESR. The 
donors gave the blood voluntarily without being payed. The age range was 18 t o  65 
years; mean 35.9 years for women and 39.3 years for men. 198 donors were 
investigated twice with an interval of six months. The present results have been 
published in another form before (1). 

Results 

The geometric mean was 4.5 mm/hour for women and 2.5 mm/hour for men. The 
median value increased with age for both men and women. In Fig. 7.7.1 the 97% 
percentile for the ESR-values are shown as function of age. 

Intra-individual variation was investigated in 198 subjects using the difference 
between first and second sampling. The coefficient of correlation was 0.26 for males 
and 0.58 for females. 

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Erythrocyte Sedimentation Rate (mmlh) 

30 -I Women --- I 
I 
I 

I 

Women Men 

15 

l o  1 Men 
5 1  
O J  

I I I I 1 1 

20 30 40 50 60 70 

Age (years) 

Fig. 7.7.1 97% percentile for ESR as function of age for healthy men and 
women. 

Discussion 

The sedimentation rate is often applied as a 'screening test' in order to identify latent 
diseases, as the expectation is a quantitative connection between the degree of disease 
and the enhance increase in of the sedimentation rate. 

However, before the test can be applied, it is necessary to know the distribution of test 
results in the actual population in order to determine the validity of the test. Like all 
other reference intervals a fraction of 'defined healthy' individuals will be excluded 
due to test results outside the reference interval. By using a one-tailed model - 
excluding the upper 2% percentage of individuals the 'discharged' fraction is kept at a 
low level. 

3 74 



These limits are used as rule-out criteria in the protein investigations (cf. sections 7.2, 
7.3 and 7.4). 

References 

1. Dalhpj J, Wiggers P. The erythrocyte sedimentation rate in clinically healthy individuals. Ugeskr 
k g e r  1990;152:456-9. 

Westergren A. The technique of the red cell sedimentation reaction. h e r  Rev Tuberc 1926;14: 
94-101. 

2 .  

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