Over a 16 month period 307 children with suspected tuberculosis (TB) and an
available full blood count (FBC) seen at Tygerberg Hospital in South Afric
a were evaluated and categorized as confirmed (A), probable (B), and no TB
(C) according to WHO criteria. There was no difference in the mean age of t
he 168 group A (33.6 months), 83 group B (34.4 months), and the 56 group C
(31.6 months) children. A lower mean haemoglobin (Hb 10.2 vs. 10.8 g/dl) wa
s the only significantly different haematological parameter in children wit
h TB compared with the comparison group (Group C). There were no difference
s in median total white cell count, neutrophils, lymphocytes, monocytes, pl
atelets, or the proportion of children in each group with anaemia, microcyt
osis, neutrophilia, neutropenia, lymphocytosis, lymphopenia, monocytosis, t
hrombocytosis or thrombocytopenia. The most common haematological abnormali
ties in children with TB were the presence of anaemia, neutrophilia, and mo
nocytosis but these changes were found with equal frequency in control pati
ents. Although haematological abnormalities are fairly common in children w
ith TB, in a developing country these abnormalities also occur frequently i
n children with other non-tuberculosis respiratory infections. An FBC has n
o diagnostic predictive value when investigating a child for TB.