| |
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.
|
