Blood Parameters Elevated in Tuberculosis
In active tuberculosis, the most consistently elevated blood parameters include inflammatory markers (C-reactive protein, erythrocyte sedimentation rate), white blood cell count with neutrophilia, neutrophil-to-lymphocyte ratio (NLR), red cell distribution width (RDW), platelet factor 4, fibrinogen, and liver transaminases (ALT/AST), while hemoglobin is typically decreased due to anemia of chronic disease.
Inflammatory Markers
- C-reactive protein (CRP) is significantly elevated in patients with active pulmonary tuberculosis, with higher levels correlating with more advanced disease 1
- Neutrophil-to-lymphocyte ratio (NLR) is increased, particularly in advanced TB (4.7 in advanced disease versus 3.1 in mild-moderate disease, p=0.009) 1
- Red cell distribution width (RDW) is elevated, with values of 17.7% in advanced PTB compared to 15.7% in mild-moderate disease (p=0.002) 1
- Both NLR and RDW serve as useful markers of inflammation to determine disease severity and help clinically manage TB patients 1
Hematological Parameters
White Blood Cells
- White blood cell count is elevated, especially in advanced pulmonary tuberculosis 1
- Neutrophil count is significantly increased in patients with advanced PTB compared to those with mild-moderate disease 1
- Granulocyte count is increased among newly diagnosed TB patients 2
Lymphocyte Subsets
- CD4 lymphocyte count is decreased (CD4 lymphopenia), with male TB patients showing mean CD4 of 650±224 cells/µl versus 883±256 cells/µl in controls (p=0.001) 2
- Female TB patients demonstrate mean CD4 of 793±332 cells/µl compared to 975±300 cells/µl in controls (p=0.001) 2
- CD8 counts show no statistically significant difference between TB patients and controls 2
Red Blood Cells and Anemia
- Hemoglobin is decreased, with 37% of TB patients developing anemia 2
- Anemia is most common in pulmonary TB (55% of anemic cases), followed by tuberculous lymphadenitis (32.5%) 2
- Normocytic normochromic anemia is the most common morphological pattern (37.5%), followed by normocytic hypochromic anemia (30.4%) 2
Hemostatic Parameters
- Platelet factor 4 (PF4) is significantly elevated in TB patients compared to healthy controls 3
- Fibrinogen levels are significantly increased in TB patients 3
- Prothrombin time (PT) is prolonged in TB patients versus controls 3
- Activated partial thromboplastin time (APTT) is prolonged in TB patients 3
- Thrombin clotting time (TCT) is significantly decreased in TB patients 3
- These abnormalities indicate activation of the hemostatic mechanism and may predispose TB patients to bleeding complications 3
Liver Function Parameters
- Hepatic transaminases (ALT/AST) are commonly elevated in TB patients, with modest elevations not uncommon in pre-treatment liver function tests 4
- Transient elevations of hepatic enzyme concentrations may be observed during the first period of anti-TB therapy 4
- Bilirubin may be elevated, particularly if drug-induced hepatotoxicity develops during treatment 4
Clinical Monitoring Implications
Important Caveats
- Liver function should be evaluated before initiating TB treatment to establish baseline values 4, 5
- If AST/ALT levels are 2 or more times normal at baseline, liver function should be monitored weekly for two weeks, then biweekly until normal 4
- Treatment should be stopped if AST/ALT rises to 5 times normal or bilirubin rises, regardless of symptoms 4, 6
Monitoring During Treatment
- PF4, TCT, and fibrinogen improve significantly as anti-tuberculosis therapy progresses and may serve as markers for monitoring treatment response 3
- Platelet count, PT, and APTT remain unchanged during treatment despite clinical improvement 3
- IFN-gamma responses measured by whole-blood assays show inconsistent changes during treatment and do not reliably correlate with treatment response 7