European Journal of Cardiovascular Medicine

Anemia has now become a public health problem worldwide. A study among rural population in India showed that anemia was highest among young adults and elderly (42%) and lowest among children (8.69%)¹. Anemia is also a major threat among antenatal population. It can lead to many complications like premature birth and low birth weight. Anemia is a morbid condition that affects people of all age groups and iron deficiency remains as a major threat to global health.

Manual methods are generally low cost but they are labour intensive. Inspite of the high capital cost, automated methods ensure rapid performance rates and also permits testing of large volume of samples with a small number of laboratory workers. Hemoglobin concentration may be estimated by colourimetric method, specific gravity, iron content or by oxygen combining capacity. The packed cell volume (PCV) can be used as a simple screening test for anaemia, as a reference method for calibrating automated blood count systems, and as a rough guide to the accuracy of haemoglobin measurements. Morphology of RBC can be assessed by examining peripheral smear which helps in the morphologic classification of aneimia as normocytic normochromic, macrocytic, microcytic hypochromic and dimorphic.²

Now these parameters are determined by electronic cell counters and Hb analyzers. Most of the current analyzers generate Hemoglobin, RBC count, PCV, MCV, MCH, MCHC and red cell distribution width (RDW). RDW is a quantitative measure

of the variation in red cell size³. RBC histogram is also an integral part of automated analysis which in association with RBC indices, hematocrit and RBC distribution width provides major clues in the diagnosis and management of red cell disorders⁴.

Manual examination of smear alone is time consuming and suffers inter observer variations⁵. Also detailed peripheral smear examination is not useful in differentiating conditions with similar smear findings such as iron deficiency anemia, beta thalassemia minor and anemia of chronic disease⁶. Review of smear along with a CBC print out generated by automated analyzer helps to make an accurate diagnosis in such cases. In addition there could be flags that are messages provided by the hematology analyzers indicating the presence of certain abnormalities that can be reviewed by manual smear examination

Automated hematology analyzers provide accurate and precise RBC count, red cell indices indicating size and distribution of RBC and abnormalities in any of these parameters will be generated as flags by the machine.⁷

The rate of smear review could also be brought down from 7.2% to 2.6% by proper clinical data in addition to CBC thereby reducing the turn around time for results by doing automated CBC count alone without an observable loss in diagnostic efficacy.

However despite high precision and accuracy of hematology analyzers, manual slide review is still necessary for identifying some abnormalities. Peripheral smear examination should be done as a supplement to automated CBC and the evaluation provides a synopsis of essentially all other hematology parameter values and assurance of the accuracy of values obtained by other methods. Hence each laboratory should set its own criteria to decide when to perform a manual smear review and optimize them to maximize efficiency.

Consecutive peripheral smear examination and automated complete blood counts complement each other for providing a comprehensive report.

The present study is an attempt to compare the manual methods with the automated methods in the diagnosis of anemia.

This study is a descriptive study that was done for a period of one and a half years, at Government Medical College, Alappuzha, after getting ethical clearance. Patient data was collected on the basis of clinicians requisition form accompanying the blood samples sent to the Dept. of Pathology Hence study was eligible for consent waiver according to ethical committee. Sample size was fixed at 200.First 200 EDTA blood samples with Hb<12gm/dl by automated method was included in the study population. Hemoglobin was then estimated by Sahli’s method. Smears were then examined under microscope and RBCs were morphologically categorized into Normocytic, Microcytic and Macrocytic.

After morphological categorization of anemia by peripheral smear, it was compared with values generated by automated hematology analyser Sysmex XS Series namely MCV, MCH, MCHC, RDW and RBC histogram. The values generated by manual and automated method were then compared. Statistical analysis was done using SPSS software.

The sex distribution of anemia was found to be equal in our study.

Out of the total 200 peripheral blood smears examined, 134 cases (67%) were normocytic normochromic anemia, 52 cases (26%) were microcytic hypochromic anemia and 14 cases (7%) were macrocytic anemia.

On comparing findings of peripheral smear with parameters of automated method, the following results were obtained

Table 10: Comparison of morphological typing of anemia by manual and automated method

On Automated analysis, following results were obtained

Out of the total 142 normocytic normochromic anemia, only 132 cases (93%) were normocytic on peripheral smear examination and 10 cases (7%) were microcytic

On Automated analysis 44 cases were Microcytic hypochromic, of which 42 cases (95.5%) were microcytic on peripheral cases and 2 cases (4.5%) were normocytic

Out of 14 macrocytic anemia by automated method, all were macrocytic in peripheral smear also.

On statistically analysis p value was found to be less than 0.0001 according to chi square test implying significant association between parameters obtained by manual and automated method.

Kappa Measure of Agreement between manual and automated method was 0.87 with a p value <0.0001.So there was statistically almost perfect agreement.

Figure 1: Normocytic Normochromic Anemia

Figure 2: Microcytic Hypochromic Anemia

Figure 3: Macrocytic Anemia

Figure 4: Macrocytic Anemia with hypersegmented neutrophil

Anemia is a major public health problem worldwide. Measurement of any of the three parameters namely haemoglobin, haematocrit and RBC counts can be used to detect the presence of anemia along with morphological characterisation of anemia by examining peripheral smear.

Now these parameters are determined by automated method. Electronic cell counters generate red cell indices and red cell histogram providing an idea about morphology of RBCs. Peripheral smear findings are usually correlated with complete blood counts by automated analyser.

Automated values can provide a clue regarding the morphology of anemia and thus can serve as an important screening tool especially when a large population is screened for anemia. Thus it is important to know the utility of automated analyser and to correlate peripheral smear findings and automated values.

Automated hematology analyzers provide accurate and precise RBC count, red cell indices indicating size and distribution of RBC and abnormalities in any of these parameters will be generated as flags by the machine⁷.

Samuel Ricardo Comar et al. in their study discussed the importance of automated hematology analyzers and aimed at developing a screening criteria for manual blood smear examination thereby reducing the number of automated blood counts requiring manual blood smear examination thereby reducing the human interaction and the delay in results⁸. The rate of smear review could also be brought down from 7.2% to 2.6% by proper clinical data in addition to CBC thereby reducing the turnaround time for results by doing automated CBC count alone without an observable loss in diagnostic efficacy⁹.

Cell counters have now become a vital part in medical laboratory services improving efficacy and decreasing cost.

Histogram is used as a visual aid along with peripheral smear for assessing morphological changes. Histogram displays morphological changes as peaks, points or valleys thus leading to a quick and cost-effective diagnosis.

RBC histogram will provide a diagnostic hint and is a powerful screening tool and is supplementary to peripheral smear examination for correct diagnosis of RBC disorder. RBC histogram along with other CBC parameters especially MCV and RDW is very useful in diagnosis and management of various RBC disorders. A comparative study of red cell histogram along with CBC parameters and peripheral smear by Sarita Choudhary et al. showed high concordance in typing of anemia by peripheral smear and automated method¹⁰.

However, despite high precision and accuracy of hematology analyzers, manual slide review is still necessary for identifying some abnormalities. Peripheral smear examination should be done as a supplement to automated CBC and the evaluation provides a synopsis of essentially all other hematology parameter values and assurance of the accuracy of values obtained by other methods. Hence each laboratory should set its own criteria to decide when to perform a manual smear review and optimize them to maximize efficiency.

In his study, Gene Gulati et al. concluded that blood smear evaluation along with complete blood count is essential to ensure that no clinically significant finding is missed¹¹.

Another study by Mauro Buttarello et al. also concluded that though automation is essential in modern hematology laboratory, a microscopic control of the sample is also needed for diagnosis. Knowledge about the hematology analyser in use is also essential so as to know its limitations which will help in correct interpretation of results¹².

Consecutive peripheral smear examination and automated complete blood counts complement each other for providing a comprehensive report.

In a study conducted by Shruti Singla et al. showed that relationship between histogram pattern and peripheral smear findings in dimorphic anemia pose certain queries regarding the validity of histograms and hence peripheral smear examination along with values generated by automated method is essential for diagnosing hematological disorders¹³.

So, RBC histogram combined with red cell indices are useful tools to guide the technicians to know which case actually needs peripheral smear review by experts and also provide a diagnostic clue towards morphological categorization of anemia.

It is very clear from the present study that the automated results are comparable with the manual methods used in the diagnosis of anemia. Automated method reduces workload and turnaround time and thus save time. However, the amount of extra information gathered from a peripheral smear examination cannot be overlooked. So automated methods should not completely replace peripheral smear examination. In addition, there could be flags that are messages provided by the hematology analyzers indicating the presence of certain abnormalities that should be reviewed by manual smear examination. Hence for a meaningful interpretation of CBC print out, peripheral smear examination is also essential. Hence peripheral smear examination along with CBC parameters provides a better approach in the diagnosis of anemia.

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