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Laboratory Tests

Should laboratory studies be obtained?

Author, date, country, and industry of funding

Patient Group

Strength of Evidence (GRADE)

Research design

Significant results


(Aydogan, Aydogan, Kara, Basim, & Erdogan, 2007)



Children mean age 4 ±3.6 y (range 6 m-13 y)

Presenting with first afebrile seizure

Very low

Prospective cohort All subjects with afebrile seizure  between Jan 2000 and March 2002 were enrolled

62 subjects were enrolled- 50% male

9 subjects had leukocytosis (14.5%), a second CBC was obtained and leukocytosis did not persist.


Leukocytosis was more prevalent in children with status epilepticus


SE defined as a continuous seizure lasting longer than 30 minutes or repeating seizures last 30 minutes with recovering consciousness between them.

Small number of subjects.


(Landau, Waisman, & Shuper, 2010)


85 subjects average age 7.5 y (range 0-18 y) who made 104 visits to the ED

Excluded febrile seizure or other primary diagnosis

Very Low- inconsistent includes subjects that do not apply to this guideline

Retrospective chart review

Laboratory tests were obtained in 84% of visits. Eight percent provided useful information and < 5% were helpful in diagnosis and management.

Only one lumbar puncture was performed.

Eight percent of visits had electrocardiography performed and all were normal

Seven percent of visit had electroencephalography performed and was consistently useful and was always performed along with a neurology consultation

Mix of children with first seizure and those already on medication for seizure. Only 30 (35%) subjects presented with first seizure.

(Nypaver, Reynolds, Tanz, & Davis, 1992)1


308 ED charts,

108 febrile (mean age 2.1 years)

200 non febrile seizures. (mean age 5.7 years

Included lab tests: electrolytes

Calcium, magnesium, ammonia, glucose, Dextrostix

Very Low

Retrospective chart review

41 were having their first non febrile seizure. 26 subjects (63%) had at least one laboratory test performed.

No changes in therapy were made as the result of the laboratory findings.

In 1992 US dollars, the mean cost of the laboratory tests was $122.00 per subject.

Small sample size.

Important changes in newborn screening since this study need to be considered, that is the need for lab studies may be even lower.

Scarfone 2000 USA

Infants < or equal to 12 months of age presenting to the ED of a tertiary care children’s hospital.

Serum chemistry results were classified as normal, outside of range normal and clinically significantly abnormal

Very Low

Retrospective chart review

214 patient visits made by infants with febrile and non febrile seizures.

134/214 were non-febrile seizures and

70 of these were a first seizure, or 52% of all presenting non febrile seizures.

51 of 70 had lab drawn

8/51 (16%) had a clinically significant abnormality.


Is there a Working Group on Status Epilepticus recommendation that serum chemistries should be obtained for adults and children with status epilepticus?

Would expanded newborn screening change any of this?

(Valencia et al., 2003)

Urban hospital, All children unprovoked seizure. Prospective 

Very Low

Prospective chart review

Separated out those with history of seizure from those with first seizure

Total of 107 children met criteria.

Mean age 6.6 years (range 0.1-20 years).

58% male

42% Black

33% Hispanic

19% White

7% Other


75% (N=80) had previous seizures

68% of these were taking anti epileptic medications


For those who had chemistries drawn

2/33 in the previous seizure group had abnormal electrolytes

For those who had chemistries drawn 5/21 in the no previous seizure group had abnormal electrolytes.


Patients with abnormal electrolytes were significantly younger (mean age 1.7 vs. 7.2 years) symptoms included vomiting or diarrhea, or presented with a changed in mental status.


These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.