Quantitative C-reactive protein (CRP) in pulmonary tuberculosis.

Abstract

Serum CRP values were determined by the ICS rate nephelometric method in 18 cases of active pulmonary tuberculosis, 12 cases of healed pulmonary tuberculosis, 31 normal persons and in 26 cases with other pulmonary bacterial infections. The study revealed the following information. (A) The means±SD of CRP values in patients with active tuberculosis, healed tuberculosis, other bacterial infections and in normal persons were 15.41±8.77, 6.61±3.32, 228±63 and 1.42±0.95μg/ml, respectively. (B) The ranges of serum CRP values in patients with active tuberculosis, healed tuberculosis, other bacterial infections and in normal persons were 5-32, 3-10, 110-340 and 0-3μg/ml, respectively, by the principle of the 95 percentile. (C) A significant difference (p＜0.01) of CRP values occurred between patients with active and healed tuberculosis. (D) An 83% sensitivity and 75% specificity in the differentiation between patients with active and healed tuberculosis occurred by setting 7μg/ml as a cut off value, thus, it is inferred that a CRP value of 7μg/ml may be suggested as a cut off value for making decisions about when to stop anti-tuberculosis drugs. (E) A significant difference (p＜0.01) of CRP values occurred between patients with active tuberculosis and other bacterial infections. The ranges of CRP values in these two groups did not overlapped, thus, it is inferred that differential diagnosis between patients with active tuberculosis and other bacterial infections can be made by a range of CRP value in the 95 percentile. (F) No significant difference of CRP values among the four active tuberculosis groups (exudative-fibrotic pattern, cavity, pneumonia and effusion) (H＝2.2, NS) was evident. (G) No relationships were found to exist between CRP values and ESR (rs＝0.28, NS) or CRP values and leukocyte counts (rs＝0.63, NS).