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Serum Lactate as a marker for mortality in patients presenting to the ED with infection.

Three Part Question

In [a patient presenting to the emergency department with infection] is [serum lactate] a [predictor of mortality]?

Clinical Scenario

A 40 year old male presents to the emergency department with a 4 day history of cellulitis of the lower extremity, fever and chills. How useful is an initial serum lactate concentration drawn in the ED as a predictor of mortality?

Search Strategy

Medline 1950-2007 April Week 1 using the OVID interface.
Cochrane Database of Systematic Reviews and Cochrane Central register of Controlled Trials, April 2007
[(lactic or exp Lactic Acid/) OR ( OR (exp Acidosis, Lactic/)] AND [(exp Infection/ or OR ( or exp Sepsis/) OR (septic or exp Shock, Septic/ OR severe] AND [(emergency medical or exp Emergency Medical Services/) OR (exp Emergency Service, Hospital/ or emergency]

Search Outcome

18 papers were found on Medline, of which 2 were relevant.
No additional papers were found in the Cochrane Library.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Shapiro et al.
May 2005
1278 patients in an urban academic medical center: 18 years or older, admitted to the hospital with a suspected infection-related diagnosis, having had serum lactate level drawn at initial presentation in the ED. Patients stratified according to lactate. Low (L) <2.5 mmol/L, medium (M) 2.5-3.99 mmol/L, high (H) >/= 4 mmol/L.Prospective cohort study. Level IIb evidence.Death at 28 daysL=43/877 (4.9%) (95% CI 3.5%-6.3%), M=24/267 (9.0%) (95% CI 5.6%-12.4%), H=38/134 (28.4%) (95% CI 21%-36%)Patients without lactate drawn at presentation were not included. Only patients admitted to the hospital were inlcuded. No patient demographics or measures of illness severity provided.
Sensitivity (Sn) and specificity (Sp) for death at 28 daysLactate >/= 2.5 Sn=59% (95% CI 50%-68%), Sp=71% (95% CI 69%-74%), lactate>/= 4, Sn=36% (95% CI 27%-45%), Sp=92% (95% CI 90%-93%)
Death within 3 daysL = 13/877 (1.5%) (95% CI 0.7%-2.3%), M = 12/267 (4.5%) (95% CI 2.0%-7.0%), H = 30/134 (22.4%) (95% CI 15%-29%)
Sensitivity (Sn) and specificity (Sp) for death within 3 daysLactate >/= 2.5 Sn=76% (95% CI 65%-88%), Sp=71% (95% CI 68%-73%), lactate>/= 4, Sn=55% (95% CI 41%-68%), Sp=91% (95% CI 90%-93%)


An initial serum lactate may be useful in risk stratification in patients presenting to the emergency department with infections. Conversely, it may be a covariate of another clinical marker. There appears to be an increasing trend of mortality with elevated initial lactate levels. 22.4% patients with an initial lactate level > 4.0 mmol/L died within 3 days.

Clinical Bottom Line

Initial serum lactate levels drawn in the ED may serve as an overall marker of mortality in patients admitted to the hospital with an infection-related diagnosis.


  1. Shapiro NI. Howell MD. Talmor D. et al. Serum Lactate as a Predictor of Mortality in Emergency Department Patients With Infection Annals of Emergency Medicine 2005,45:524-528.