Percentage of hyperdense cells: Automated parameter to hereditary spherocytosis screening.

BACKGROUND

The hereditary spherocytosis (HS) is a common cause of inherited hemolytic anemia that is difficult to identify in many cases. Currently, there are new economic parameters for red cell disorder evaluation, such as hyperdense cell percentage (%Hyper) obtained from automated analyzers.

OBJECTIVE

In this study we determined the %Hyper efficacy and compared its accuracy with a flow cytometry method in HS, hemoglobinopathy and healthy individuals, in order to allow the use of %Hyper in HS screening.

METHODS

Patients treated at the outpatient clinic at the Hospital de Clínicas de Porto Alegre (HCPA) were allocated into three groups according to their clinical condition: HS, hemoglobinopathy or healthy groups. Flow-cytometric osmotic fragility test (FCM OF) method was used as reference to compare with %Hyper, both performed from K2EDTA samples.

RESULTS

Fifty-eight individuals were included in this study. We found that the %Hyper cut-off point of 6.4% showed an excellent sensitivity (92.3%) and specificity (90.7%) to detect HS. Besides, %Hyper presented a significant negative correlation with FCM OF in identifying HS (Rs=-0.525; P<0.001).

CONCLUSIONS

%Hyper could be a tool for screening HS, before requesting additional tests. It is a fast and cost-effective test, which is easily obtained in complete blood count, favoring its use in clinical laboratories. However, this test does not replace flow cytometric methods for confirmation of atypical cases.