Counts and appearance provide different information
A complete blood count measures blood cell parameters. A peripheral blood smear, also called a blood film, allows examination of cell appearance. It can add information about size, shape, staining and the types of cells present. [1,2]
A request for a smear does not mean the automated analyser has failed. The two investigations can contribute different information to the same clinical question.
Why a smear may be requested
Microscopic review may help assess an abnormal count, investigate a suspected blood disorder or look for particular findings such as blood parasites when clinically indicated. The report must be considered with the history and other investigations. [1]
For patients, ask what question the additional examination is intended to answer. Avoid assuming that a smear request necessarily means cancer is suspected.
Read the descriptive language in context
Terms describing red cell size or shape are observations. Their significance depends on the overall pattern and clinical setting. Several conditions can share morphological features, so one descriptive word should not be treated as a complete diagnosis. [1,2]
Keep the smear report with the corresponding CBC, including the sample date. This helps the clinician relate morphology to the measured counts.
What should the next discussion cover
Ask whether the findings explain the original concern and whether targeted investigations are needed. If you already have previous reports, bring them so the clinician can review the trend.
For referring professionals, provide the reason for testing and relevant illness or treatment history. A focused request helps the laboratory direct attention to the clinical question without restricting appropriate assessment of the rest of the film.
Use the result to guide a decision
The useful outcome is a clearer interpretation and a plan. The additional investigation should help decide whether to observe, investigate further or arrange specialist review. Understanding that purpose is more helpful than reading individual terms from the report without context.
References
[1] MedlinePlus. Blood Smear. Read source
[2] MedlinePlus Medical Encyclopedia. Blood smear. Read source