Guidelines for Microbiology & Virology - IU Health

Specimen Preparation and Collection Section 3
General Guidelines for
Blood Culture Collection
TABLE 4: Recommendations for Blood Culture Collection
Clinical Condition Collection Protocol Comments
For Adults/Adolescents
Severe Septicemia (2) Cultures prior to therapy One (1) 10-15 ML sample from each arm
Acute Endocarditis
(2) Cultures w/in 1-2 hr. of Space each collection at least 1 hr. apart with two
Subacute endocarditis
Low grade intravascular
infection
Bacteremia of unknown origin
Patient on therapy
evaluation and prior to therapy
(2) Cultures w/in 24 hr. on
day (1). If negative 24 hr. later,
obtain (2) more
(2) separate venipunctures
Space each collection at least 1 hr. apart. Patients
receiving antibiotics prior to admission, obtain two
(2)separate cultures on each of three (3) successive
days. Cultures should be incubated at least (14) days.
*NOTE: contact the microbiology lab when cultures
need to be held longer than (5) days.
(2) Cultures w/in 24 hr. Specimens should be collected at Least 1 hr. apart
at first sign of febrile episodes.
(4) Cultures w/in 48 hr. Take specimen immediately prior to next dose of
antibiotic. Cultures should be incubated for at
least (14) days *NOTE: contact the microbiology
lab when cultures need to be held longer than (5) days
Febrile Episodes
No more than two (2) total
cultures
Bacteremia may precede episodes of fever and
chills by about one (1) hr.
Small Children (< 4 years) 1-2 ML. samples (2) Cultures usually suffice for diagnosing bacteremia
in the newborn. Less than 1 mL of blood will detect
Bacteremia when concentration of organism is
sufficiently high. If so, inoculate (1)Peds Plus bottle.
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The volume of blood for culture is critical! Concentration of organisms in most cases of Bacteremia is low, especially
if the patient is on antimicrobial therapy.
Most cases of Bacteremia are detected using 2 sets of separately collected blood cultures. More that 2 sets yield little
additional information.
In children less than four, the concentration of organisms during bacteremia is higher than those four years and older;
therefore, less blood is acceptable for culture utilizing the Peds Plus bottles.
The yield of blood cultures in adults increases approximately 3% per ml of blood cultured. Culture bottles with
inadequate blood volumes may demonstrate no growth when in fact microorganisms are present in the blood. To
accurately ascertain bacteremic episodes and obtain the best sensitivity, the maximum amounts of blood (specified on
the collection bottles) should be obtained for culture.
One blood culture “set” is defined as a sample of blood drawn at a single time at a single site, regardless of how many
bottles are injected into. These “sets” typically should be collected ten minutes apart unless ordered otherwise. For
blood cultures obtained from an intravascular line it is permissible to obtain both “sets” with one large volume draw.
Ideally blood cultures are obtained from peripheral venipuncture (i.e. - two sets from two separate venipunctures).
Draw blood cultures prior to initiating or changing antimicrobial therapy if at all possible.
Aseptic technique is critical to obtaining accurate results. When obtaining specimens via skin puncture, a second person
may be needed to assist in extremity stabilization and to place blood into bottles while pressure is held over puncture site.
Inpatient Collection Policy
RN’s, LPN’s, AST’s, house staff or physicians who have received competency validation in blood culture specimen
collection may draw Blood cultures.
A physician’s order is required to obtain blood cultures from an intravascular line. It is critical to label the specimen with
the specific line it is drawn from (eg - arterial, PICC, etc.).
Blood can be collected from veins, arteries, or intravascular catheters
Modified March 2010 - 6 -