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Full blood count and reticulocyte count in painful sickle crisis

Three Part Question

In a [patient with painful sickle crisis] does a [complete blood count or reticulocyte cell count] alter [management decisions]?

Clinical Scenario

A 25 year old man with sickle cell disease presents with a two day history of pain in his arms and legs. His pain is consistent with his usual painful crisis symptoms. He is afebrile, has normal vital signs, and has no acute findings on physical exam. You promptly treat his pain. You order haematologic tests in these situations as a matter of routine. You wonder if the results of his complete blood count or reticulocyte count will alter your management.

Search Strategy

Ovid MEDLINE 1966 to January Week 3 2006
EMBASE 1980 to 2006 Week 04
The Cochrane Library Issue 1 2006
OVID:[exp anaemia, sickle cell/ OR sickle adj cell.mp.] AND [exp emergency service, hospital/ OR emergency department.mp. OR exp emergencies/] AND [exp Reticulocyte count/ OR exp Blood cell count/] Limit to Humans and English language
Cochrane:[Anemia, Sickle Cell (MeSH explode all trees)] AND [Blood cell count (MeSH explode all trees) OR Reticulocyte Count (MeSH explode all trees)]

Search Outcome

The search yielded 21 articles. Bibliographic references found in these articles were also examined to identify pertinent literature. Only original research articles were included. Three articles directly addressed the question

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Lopez BL
1996
USA
117 patients with 323 presentations in a two part study. The first part was 53 patients with 119 presentations. The second part was 64 patients with 204 presentations. All study patients had a complete blood count and reticulocyte count done.Part one: Retrospective chart review Part two: Prospective studyHaematologic differences between admitted and discharged patientsNone on retrospective review

Higher mean white blood cell counts but no difference in the presence of significant infections during the prospective study.
Small size Institutional bias in regards to admission decisions and white blood cell count. No cases of aplastic anemia.
Wells BL
2002
USA
34 adult patients with 101 presentations. All patients had a complete blood count and a reticulocyte count done. The physician was initially blinded to the results of the reticulocyte count.Prospective studyManagementNo management was changed based on reticulocyte count data.Small Size No cases of aplastic anemia.
Suspicion of aplastic anemiaNo patients were suspected to have aplastic anemia before or after reticulocyte cell count was available.
Chapman JI
2004
USA
30 children with 86 presentations. A complicated presentation was defined as one that required admission, antibiotics, blood products, or resulted in acute chest syndrome within forty-eight hours.Retropective studyHaematologic differences between complicated and uncomplicated patientsNoneRetrospective Small size

Comment(s)

Haematological testing in the evaluation of sickle cell patients presenting with painful crisis frequently includes a complete blood count and reticulocyte cell count. Furthermore, this testing is often ordered on a routine basis, defined here as not specifically indicated by patient history or physical examination alone. This routine testing is performed with the thought that it will detect occult illness, such as aplastic anemia or infection, and alter patient management. The literature reviewed here excluded patients presenting with ill appearance, fever, or abnormal vital signs because haematologic testing in such situations is more standardized. The studies reviewed do not support the practice of routine haematologic testing in sickle cell patients presenting with painful crisis. With the exception of part two of the study by Lopez et al., which had significant bias involved, the complete blood count and reticulocyte cell count did not alter management decisions made by physicians. The literature also found no value in the ability of these tests to detect occult illness. Notably though, the studies reviewed have a paucity of patients with complications such as significant occult infection or occult aplastic crisis. The lack of events may represent appropriate patient selection in that patients with these complications often present with abnormal vital signs or illness specific symptoms. It is possible the exclusion criteria described above removed patients with these complications from the study population. Alternatively, sample sizes may have been too small to capture these rare events.

Clinical Bottom Line

The routine use of complete blood count and reticulocyte count in sickle cell patients presenting with painful crisis does not alter management decisions. Selective use of these tests can be based on patient age, reported symptoms, vital signs, physical examination, and clinical judgment.

References

  1. Lopez BL, Griswold SK, Navek A, et al The complete blood count and reticulocyte count are they necessary in the evaluation of acute vasoocclusive sickle-cell crisis? Academic Emergency Medicine 1996;3:751-757.
  2. Wells BL, Vizioli TL, Counselman FL The reticulocyte count: Is it needed for evaluating typical sickle cell crisis presenting to the ED? American Journal of Emergency Medicine 2002;20:69-70.
  3. Chapman JI, El-Shammaa EN, Bonsu BK The utility of screening laboratory studies in pediatric patients with sickle cell pain episodes Am J Emerg Med. 2004;22:258-263.