Hi. An elevated white blood cell count (called leukocytosis) without any accompanying symptoms can have various causes. The most common type of asymptomatic leukocytosis is what is termed as "reactive", which means that the increase in white cell count is a reaction to some ongoing infection or inflammation. Other causes include obesity, physical or emotional stress, and intake of certain medications like steroids, some asthma medications (beta-agonists), and lithium (a drug used for manic-depressive disorder).
A persistent leukocytosis may also be a symptom of a blood disorder like chronic leukemia. The LAP (leukocyte alkaline phosphatase) score is used to differentiate leukocytosis which is due to chronic leukemia with those due to inflammation/ infection. Reactive leukocytosis usually has a normal or elevated LAP score, while chronic leukemia tends to have a low LAP score. Your LAP score of 174 is elevated (normal value: 25-130) so your leukocytosis is most probably not due to leukemia, but to a benign condition.