Hematologic Scoring for Diagnosis of Neonatal 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)

(1a) 0-12 hours: (-65.27778 * ((hours)^2)) + (1475 * (hours)) + 6100

(1b) 12-60 hours: (0.0400992 * ((hours)^2)) - (155.14 * (hours)) + 16223.097

(1c) 60-120 hours: (-26.6667 * (hours)) + 8600

(1d) > 120 hours: 5400

(2) total PMN count, lower limit of reference range (data for 0 hours to 28 days)

(2a) 0-12 hours: (525 * (hours)) + 1800

(2b) 12-60 hours: (-104.1667 * (hours)) + 9350

(2c) 60-72 hours: (-108.333 * (hours)) + 9600

(2d) > 72 hours: 1800

(3) immature PMN count, upper limit of reference range (data is only for 0-60 hours)

(3a) 0-60 hours: (-0.000409 * ((hours) ^4)) + (0.0612068 * ((hours) ^3)) - (3.29594 * ((hours) ^2)) + (58.266641 * (hours)) + 1106.8531

(3b) 60-168 hours: 600

(4) immature-to-total PMN ratio, upper limit of reference range (data is only for 0-60 hours)

(4a) 0-34 hours: (-0.000353 * (hours)) + 0.1624738

(4b) 34-60 hours: (-0.001145 * (hours)) + 0.1880431

(4c) 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