Is anal swab nucleic acid test more accurate than nasopharyngeal swab?
Nucleic acid detection:generally carried out by sampling pharyngeal swabs in the nasal cavity and oral cavity.
Now began to increase the anal swab test, we are also curious about this test method. So, is anal swab nucleic acid detection more accurate than nasopharyngeal swab? How to sample for anal swab test?
Is the nucleic acid detection of anal swab more accurate than that of nasopharyngeal swab?
In the screening of New Coronavirus pneumonia, we mainly used the oropharyngeal swab nucleic acid test. Because the reason is convenient and quick, suitable for large-scale screening. The accuracy of nasopharynx swab for new crown nucleic acid detection is higher than that of oropharyngeal swab, but the human body feels uncomfortable.
In last year’s test, researchers found that many infected people had negative pharyngeal nucleic acid.But their anal swabs were still positive for longer.
The combination of the two in nucleic acid detection can improve the detection rate and reduce the proportion of missed diagnosis.
However, anal swab sampling is inconvenient and not suitable for large-scale screening and testing in the community.
For some asymptomatic or mild infections, the condition recovers quickly after infection. And the pharyngeal nucleic acid may not be detected in 3 to 5 days.
The researchers found that the duration of nucleic acid positive in feces or anal swabs of some infected people was longer than that in the upper respiratory tract.
Therefore, increasing anal swab nucleic acid detection can improve the detection rate of infected patients and reduce missed diagnosis.
Although nucleic acid detection has the advantages of high sensitivity and short detection cycle, it also has some disadvantages.
Different from the direct isolation of live virus from human body, nucleic acid detection adopts an indirect method, which may cause false negative.
Anal swab & test tubes
How to sample for anal swab test
1. Soak the swab in normal saline, insert it into the anus of 2-3 cm, wipe it from the folds around the anus, or rotate it gently in the anus. And then insert it into the test tube containing normal saline.
2. For fecal swab culture, all the above operations require the use of sterile equipment and the swab into a sterile test tube.
