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 Hemoglobin values Total <70g/L >=70g/L Clinical Anemia Yes 23 (A) 66 (B) 89 (A+B) No 20 (C) 634 (D) 654 (C+D) Total 43 (A+C) 700 (B+D) 743 (A+B+C+D)
 Sensitivity = A/A+C = 23/43 = 53.4% Specificity = D/B+D = 634/700 = 90.6% Positive Predictive Value = A/A+B= 23/89 = 25.8%
From Yip, R. 1994
These methods present some advantages and disadvantages in assessing iron deficiency anemia in populations, which mainly depend on the population characteristics and prevalence, and on the purpose of the assessment.
In a developing country setting, especially in rural populations, biochemical procedures are not always feasible for routine use. Clinical examination may be the only means to identify anemic in these cases.
Yip et al analyzed sensitivity, specificity and positive predictive value of clinical anemia versus Hemoglobin values, as shown in the table:
In this case, even when 25.8% among those diagnosed as anemic are real anemic (PPV) by clinical examination, treating false positives in a high prevalence area will also benefit them. This is based on the assumption that the anemic population represents the most severely affected, but treating false positive subjects will also benefit them considering that they are likely to be deficient.

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