WordNet records no synonym and no antonym for differential blood count. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
counting the number of specific types of white blood cells found in 1 cubic millimeter of blood; may be included as part of a complete blood count
Synonyms, antonyms and the broader and narrower relations for differential blood count come from Princeton University’s WordNet. Full sources and licences.