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Overview :
Sepsis occurring in newborn infants can be suspected based on
hematologic findings. A scoring system can be used to quantitate these findings,
with higher scores indicating greater risk for sepsis.
Testing:
(1) white blood cell and platelet counts
(2) white blood cell differential count
(3) nucleated red blood cell count (to correct white blood
cell count)
(4) assessment of neutrophil morphology for degenerative
changes
|
Parameter |
Finding |
Score |
|
total WBC count |
<= 5,000 per µL |
1 |
|
|
>= 25,000 per µL at birth
>= 30,000 per µL at 12-24 hours
>= 21,000 per µL at day 2 onward |
1 |
|
total PMN count |
no mature PMNs seen on blood film |
2 |
|
|
increased or decreased |
1 |
|
immature PMN count |
increased |
1 |
|
immature-to-total PMN ratio |
increased |
1 |
|
immature-to-mature PMN ratio |
>= 0.3 |
1 |
|
degenerative changes in PMNs |
>= 3+ for vacuolization, toxic granulation or Dohle
bodies |
1 |
|
platelet count |
<= 150,000 per µL |
1 |
where:
•
Degenerative changes in neutrophils include vacuolization, toxic granulations
and Dohle bodies.
• The white
blood cell count observed should be corrected for the number of nucleated red
blood cells.
Reference ranges for neutrophil counts in newborn infants is
extracted from the figures in Manroe et al (1979) with approximating curves
calculated using JMP:
(1) total
PMN count, upper limit of reference range (data for 0 hours to 28 days)
• 0-12
hours: (-65.27778 * ((hours)^2)) + (1475 * (hours)) + 6100
• 12-60
hours: (0.0400992 * ((hours)^2)) - (155.14 * (hours)) + 16223.097
• 60-120
hours: (-26.6667 * (hours)) + 8600
• > 120
hours: 5400
(2) total
PMN count, lower limit of reference range (data for 0 hours to 28 days)
• 0-12
hours: (525 * (hours)) + 1800
• 12-60
hours: (-104.1667 * (hours)) + 9350
• 60-72
hours: (-108.333 * (hours)) + 9600
• > 72
hours: 1800
(3)
immature PMN count, upper limit of reference range (data is only for 0-60
hours)
• 0-60
hours: (-0.000409 * ((hours) ^4)) + (0.0612068 * ((hours) ^3)) - (3.29594 *
((hours) ^2)) + (58.266641 * (hours)) + 1106.8531
• 60-168
hours: 600
(4)
immature-to-total PMN ratio, upper limit of reference range (data is only for
0-60 hours)
• 0-34
hours: (-0.000353 * (hours)) + 0.1624738
• 34-60
hours: (-0.001145 * (hours)) + 0.1880431
• 60-168
hours: 0.120
(5) Some of
the choices are arbitrary, including use of straight lines to approximate data;
for immature neutrophil count and the immature-to-total neutrophil count, data
is only given to 60 hours with no mention made of 60-168 hours, where 168 hours
indicates the number of hours in 7 days.
Interpretation:
• minimum score: 0
• maximum score: 8
|
Score |
Interpretation |
|
<= 2 |
sepsis is very unlikely |
|
3 or 4 |
sepsis is possible |
|
>= 5 |
sepsis or infection is very
likely |
|