Increased monocyte counts may seen in tuberculosis, brucellosis, syphilis, typhus, malaria and many other infectious diseases. The ratio of monocytes to lymphocytes can be used to assess the activity of tuberculosis and certain other granulomatous diseases.


monocyte-to-lymphocyte ratio =

= (per cent monocytes) / (per cent lymphocytes) =

= (absolute monocyte count) / (absolute lymphocyte count)



• A normal ratio is <= 0.3.

• A ratio > 1.0 is seen in active disease and may indicate a poor prognosis.

• A ratio that is increasing suggests disease progression, while a ratio that is decreasing is seen in resolution with healing.



(1) Monocytosis is defined as an absolute monocyte count exceeding 950 monocytes per microliter.

(2) With active disease there is an absolute increase in monocytes.

(3) With recovery, the number of monocytes decreases while the number of lymphocytes increases.


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