Tests
1st tests to order
clinical diagnosis
Test
Diagnosis of tetanus is primarily based on clinical features and further testing is usually not necessary.
Result
features of tetanus
Tests to consider
serum toxin
Test
Tetanus toxin can be detected in serum, confirming a clinical diagnosis. Samples should be collected before tetanus immune globulin treatment, but treatment of clinical tetanus should not be delayed waiting for laboratory results. Absence of toxin in the serum does not exclude the clinical diagnosis.[39]
Result
positive
Clostridium tetani detection from wound tissue or swab
Test
Clostridium tetani may be detected in the infection site by direct polymerase chain reaction and strict anaerobic culture methods.[39] A negative result does not exclude tetanus.[39] A positive wound culture does not indicate whether the organism produces a toxin. The bacteria may be present without causing tetanus in patients with protective immunity.[19]
Result
presence of Clostridium tetani
serum antitoxin antibodies
Test
Demonstration of low levels of tetanus toxin antibodies in serum can support but not confirm a clinical diagnosis. Samples should be taken before tetanus immune globulin treatment, but treatment of clinical tetanus should not be delayed waiting for laboratory results.[39] Conversely, severe and fatal tetanus has been reported in patients with protective antibody levels.[41]
Result
low
spores on drug samples or paraphernalia
Test
Drug samples or paraphernalia can be tested for the presence of spores after discussion with the relevant local health authority.
Result
presence of spores
lumbar puncture
Test
If clinical diagnosis is uncertain additional investigations may be performed to exclude alternative diagnoses. In tetanus, cerebrospinal fluid (CSF) findings are usually normal, although CSF protein - immunoglobulin G - may be slightly elevated.[25][42]
Result
CSF protein may be slightly elevated
electroencephalogram
Test
If clinical diagnosis is uncertain additional investigations may be performed to exclude alternative diagnoses. In tetanus, electroencephalogram is normal.
Result
normal
electromyogram
Test
If clinical diagnosis is uncertain additional investigations may be performed to exclude alternative diagnoses. In tetanus, electromyogram may be normal or show nonspecific changes.[1]
Result
normal or may show nonspecific changes
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