Accuracy and Precision Evaluation of Thai Plastic
Microhematocrit Tubes: The First Product from Thailand
Preechaya Wongkrajang MD*, Nisarat Opartkiattikul MD,PhD*,
Wimol Chinswangwatanakul MD, PhD*, Somsak Areewatana MD**
Affiliation :
* Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
** Department of Anesthesiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background : In Thailand, the spun microhematocrit method is usually performed using glass microhematocrit tubes even
though broken glass tube during use may result in a risk of injury and blood-borne infection. The main reason is that the
safer product alternatives such as plastic microhematocrit tubes are more expensive. Now, plastic tubes for hematocrit
determination can be produced in Thailand at a much cheaper price. However, precision and accuracy studies are necessary
before being able to use them.
Objective : To compare the accuracy and precision of Thai plastic microhematocrit tubes against the routinely used glass
microhematocrit tubes and imported plastic microhematocrit tubes using spun microhematocrit method.
Materials and Method: One hundred residual EDTA blood samples from the Department of Clinical Pathology, Faculty of
Medicine Siriraj Hospital, Mahidol University, Thailand along with the three level hematology control materials were
measured with spun microhematocrit values using three different types of plastic microhematocrit tubes. This was compared
to the routinely used glass microhematocrit tubes as a gold standard.
Results : The repeated measures one-way ANOVA found no signifi cant difference between the hematocrit values from each
type of tubes with an F(1,99) = 0.667 and p-value = 0.574. Intraclass correlation coeffi cient(ICC) between four types of
microhematocrit tubes ranged from 0.996-0.998 (p-value < 0.001). Correlation coeffi cients (r) between four types of
microhematocrit tubes ranged from 0.996-0.998 (p-value < 0.05). Coeffi cient of variation (CV) for precision of both within
run and between run of Thai plastic microhematocrit tubes ranged from 1.44 to 2.17% compared to 1.39 to 4.01% of the
imported plastic microhematocrit tubes.
Conclusion : The hematocrit values determined by all plastic microhematocrit tubes can be considered relatively equivalent
to those of glass microhematocrit tubes in terms of accuracy and precision. The Thai plastic microhematocrit tubes are
economical and with the cost-benefi t over other plastic tubes of about 12 to 16 times. Therefore, the Thai plastic
microhematocrit tubes should be the choice for glass tube replacement.
Keywords : Plastic microhematocrit tube, Capillary tube, Spun hematocrit, Spun microhematocrit, Hematocrit
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