Comparison of lead levels in blood collected by using general and special tubes

Abstract

Objectives  The objective of this study was to compare the lead levels in blood samples from two types of collection tubes: general blood collection tubes (lavender top tubes) and special blood collection tubes (royal blue-top tubes).

Methods  A total of 22 samples were harvested from lead-exposed workers in the eastern region of Thailand. General demographic data of the participants was gathered by questionnaires, after which approximately 7-8 milliliters of venous blood was taken and equally divided into the two types of tubes. The samples were then analyzed using inductively coupled plasma mass spectrometry (ICP-MS) to measure the lead levels.

Results The study found no statistically significant difference between the mean values of the lead level in the blood collected in the two types of tubes. The serial mean blood lead level of the general and special tubes were 33.74 ± 27.18 mcg/dL and 35.94 ± 28.77 mcg/dL, respectively. The difference in serial mean blood lead levels in the two types of tubes was 2.20 ± 6.39 mcg/dL
(p = 0.121). Of the 22 blood samples, there were 2 samples in which lead levels in both types of collection tubes differed by more than two standard deviations and were considered outliers. When the two outliers were excluded and the data reanalyzed, the mean lead level in blood collected in general blood collection tubes and that collected in special blood collection tubes was 32.11 ± 27.67 mcg/dL and 32.61 ± 27.47 mcg/dL, respectively. The mean difference after excluding the outliers was only 0.50 ± 3.20 mcg/dl (p = 0.494).

Conclusions Lead levels in blood collected using the two types of collection tubes were not statistically different, Indicating that the different types of blood collection tubes can be used interchangeably.