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A comparison of commercially available blood tests has revealed more variability than expected, according to researchers.
The group compared basic blood tests run by commercial laboratories and found the testing service, type of test, and time of collection all influenced the accuracy of results.
Given that these tests can be used for disease diagnosis or to determine whether a patient’s medication is working, the researchers said this study highlights the importance of knowing the accuracy and variability of blood test results.
“While most of the variability we found was within clinically accepted ranges, there were several cases where inaccurate results would have led to incorrect medical decisions,” said Joel Dudley, PhD, of the Icahn School of Medicine at Mount Sinai in New York, New York.
“We hope this study will inspire the biomedical community to take a critical look at all testing variables to ensure that lab results are as robust and reproducible as possible.”
Dr Dudley and his colleagues described this study in the Journal of Clinical Investigation.
The researchers collected peripheral blood samples from 60 healthy adults at 4 separate time points within a 6.5-hour window. The samples were collected in Phoenix, Arizona, at an ambulatory clinic and at retail outlets with point-of-care services.
The team collected 14 samples per subject and used those samples to compare 22 common clinical lab tests conducted at 3 commercial labs. One lab, Theranos, offered blood tests obtained from a finger prick, and the other 2, Quest and LabCorp, required standard venipuncture draws.
More than half of the test results showed significant differences between test providers. Of the 22 tests, 15 (68%) showed significant variability between labs (P<0.002).
Triglyceride levels and red blood cell counts were among the most consistent results, while white blood cell counts and overall cholesterol levels were among the most variable.
Test results from Theranos were flagged by Theranos as abnormal 1.6 times more often than tests from LabCorp or Quest (P<0.0001). The percentages for measurements outside their normal range were 8.3% for LabCorp, 7.5% for Quest, and 12.2% for Theranos.
In addition, the researchers noted that, although they controlled subjects’ eating and physical activity, data from blood samples collected earlier in the day were sometimes significantly different from samples taken from the same subjects later in the day.
There were significant difference between measurements collected at time points 1 and 2 vs time points 3 and 4 for 13 of the 22 tests (P<0.002).
“These testing disparities occurred despite rigorous laboratory certification and proficiency standards designed to ensure consistency,” said study author Eric Schadt, PhD, of Mount Sinai.
“Our results suggest the need for greater transparency in lab technologies and procedures, as well as a much more thorough investigation of biological mechanisms that may contribute to more dynamic levels than we currently understand.” 
Photo by Graham Colm
A comparison of commercially available blood tests has revealed more variability than expected, according to researchers.
The group compared basic blood tests run by commercial laboratories and found the testing service, type of test, and time of collection all influenced the accuracy of results.
Given that these tests can be used for disease diagnosis or to determine whether a patient’s medication is working, the researchers said this study highlights the importance of knowing the accuracy and variability of blood test results.
“While most of the variability we found was within clinically accepted ranges, there were several cases where inaccurate results would have led to incorrect medical decisions,” said Joel Dudley, PhD, of the Icahn School of Medicine at Mount Sinai in New York, New York.
“We hope this study will inspire the biomedical community to take a critical look at all testing variables to ensure that lab results are as robust and reproducible as possible.”
Dr Dudley and his colleagues described this study in the Journal of Clinical Investigation.
The researchers collected peripheral blood samples from 60 healthy adults at 4 separate time points within a 6.5-hour window. The samples were collected in Phoenix, Arizona, at an ambulatory clinic and at retail outlets with point-of-care services.
The team collected 14 samples per subject and used those samples to compare 22 common clinical lab tests conducted at 3 commercial labs. One lab, Theranos, offered blood tests obtained from a finger prick, and the other 2, Quest and LabCorp, required standard venipuncture draws.
More than half of the test results showed significant differences between test providers. Of the 22 tests, 15 (68%) showed significant variability between labs (P<0.002).
Triglyceride levels and red blood cell counts were among the most consistent results, while white blood cell counts and overall cholesterol levels were among the most variable.
Test results from Theranos were flagged by Theranos as abnormal 1.6 times more often than tests from LabCorp or Quest (P<0.0001). The percentages for measurements outside their normal range were 8.3% for LabCorp, 7.5% for Quest, and 12.2% for Theranos.
In addition, the researchers noted that, although they controlled subjects’ eating and physical activity, data from blood samples collected earlier in the day were sometimes significantly different from samples taken from the same subjects later in the day.
There were significant difference between measurements collected at time points 1 and 2 vs time points 3 and 4 for 13 of the 22 tests (P<0.002).
“These testing disparities occurred despite rigorous laboratory certification and proficiency standards designed to ensure consistency,” said study author Eric Schadt, PhD, of Mount Sinai.
“Our results suggest the need for greater transparency in lab technologies and procedures, as well as a much more thorough investigation of biological mechanisms that may contribute to more dynamic levels than we currently understand.”
Photo by Graham Colm
A comparison of commercially available blood tests has revealed more variability than expected, according to researchers.
The group compared basic blood tests run by commercial laboratories and found the testing service, type of test, and time of collection all influenced the accuracy of results.
Given that these tests can be used for disease diagnosis or to determine whether a patient’s medication is working, the researchers said this study highlights the importance of knowing the accuracy and variability of blood test results.
“While most of the variability we found was within clinically accepted ranges, there were several cases where inaccurate results would have led to incorrect medical decisions,” said Joel Dudley, PhD, of the Icahn School of Medicine at Mount Sinai in New York, New York.
“We hope this study will inspire the biomedical community to take a critical look at all testing variables to ensure that lab results are as robust and reproducible as possible.”
Dr Dudley and his colleagues described this study in the Journal of Clinical Investigation.
The researchers collected peripheral blood samples from 60 healthy adults at 4 separate time points within a 6.5-hour window. The samples were collected in Phoenix, Arizona, at an ambulatory clinic and at retail outlets with point-of-care services.
The team collected 14 samples per subject and used those samples to compare 22 common clinical lab tests conducted at 3 commercial labs. One lab, Theranos, offered blood tests obtained from a finger prick, and the other 2, Quest and LabCorp, required standard venipuncture draws.
More than half of the test results showed significant differences between test providers. Of the 22 tests, 15 (68%) showed significant variability between labs (P<0.002).
Triglyceride levels and red blood cell counts were among the most consistent results, while white blood cell counts and overall cholesterol levels were among the most variable.
Test results from Theranos were flagged by Theranos as abnormal 1.6 times more often than tests from LabCorp or Quest (P<0.0001). The percentages for measurements outside their normal range were 8.3% for LabCorp, 7.5% for Quest, and 12.2% for Theranos.
In addition, the researchers noted that, although they controlled subjects’ eating and physical activity, data from blood samples collected earlier in the day were sometimes significantly different from samples taken from the same subjects later in the day.
There were significant difference between measurements collected at time points 1 and 2 vs time points 3 and 4 for 13 of the 22 tests (P<0.002).
“These testing disparities occurred despite rigorous laboratory certification and proficiency standards designed to ensure consistency,” said study author Eric Schadt, PhD, of Mount Sinai.
“Our results suggest the need for greater transparency in lab technologies and procedures, as well as a much more thorough investigation of biological mechanisms that may contribute to more dynamic levels than we currently understand.”