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PeaceHealtH laboratories

A L E R T

WHAT’S NEW?Effective Wednesday, February 20, 2013, all PeaceHealth Laboratories in Oregon and Alaska will perform immature granulocyte percentage as an additional parameter on the complete blood count with auto diff (unit code 2000).

This new parameter reflects improvements in technology now available with the latest instru-mentation, at no additional charge.

ImmATuRE gRANuLocyTE pERcENTAgE IG percentage is an automated measurement of intermediate neutrophils at the metamyelocyte, myelocyte and promyelocyte stages of matura-tion. Blasts and more mature forms (band and segmented neutrophils) are not included in the IG percentage quantitation.

Routine CBCs will now be reported with an automated 6-part differential including: ■ Neutrophils■ Lymphocytes■ Monocytes■ Eosinophils■ Basophils■ Immature granulocytes

Any slide flagged by the instruments for possible left shift, significantly elevated IG per-centage (IG% ≥2.0%), or samples that violate other rules including significantly low or high white blood cell or neutrophil counts, will con-tinue to be manually inspected by a laboratory technician.

If a slide review detects an increase in band or younger forms, it will continue to be reported as a left shift parameter (see table below). In addition, the CBC will also include separate automated measurements of mature neutrophils and younger forms.

CBC Neutrophil Parameters

Expanded Complete Blood Count Testing

February 13, 2013 - Oregon and Alaska

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Automated Differential percentage

Neutrophil percent

Immature granulocyte

percentLymph Mono Eos Baso

Includes segs/bands

Includes metas/myelos/pros

% % % %

manual “Left Shift” parameter*

Not reported if normal

Left shift 1+

Left shift 2+

Left shift 3+

Left shift 4+

0-10% 11-20% 21-30% 31-40% >40%

* Derived from manual evaluation of bands/metamyelocyte, myelocyte and promyelocyte stages of maturation.

800-826-3616 www.peacehealthlabs.org

Background Studies performed by PeaceHealth Laboratories confirm the published IG percentage normal range of 0-0.5% which will appear on the patient report. These studies have shown good correlation between manual and automated IG counts. The automated counts show much higher precision due to the large number of cells analyzed, allowing results to be reported in increments of 0.1%.

In one published study, IG percentage was found to correlate better with infection and positive blood culture results than the WBC count and was equal to the absolute neutrophil count in predicting infection. This study report-ed 35% sensitivity and 90% specificity for the IG percentage and, while confirming clinical utility, concluded that all screening parameters have low sensitivity and are not useful as sole screening tests for infection.1

Another study on neonatal samples showed that hospitalized premature infants more than seven days old are three times more likely to have a positive blood culture if any IG are present on the manual differential, or if the IG percentage exceeds 0.5% (upper limit of normal).2

QuESTIoNS?Michael Suter, MT(ASCP) SH Senior Clinical Scientist, Hematology Y 800-826-3616 ext. 8182 msuter@peacehealthlabs.org

Daniel Kerrigan, MD Hematopathologist Y 800-826-3616 ext. 8036 dkerrigan@peacehealthlabs.org

Deven Smith, MD Hematopathologist Y 800-826-3616 ext. 8289 dsmith@peacehealthlabs.org

REFERENcEs

1. Ansari-Lari M, Kickler Ts, Borowitz MJ. Immature granulocyte measurement using sysmex XE-2100. Relationship to infection and sepsis. Am J clin Pathol. 2003;120: 795–799.

2. Nigro KG, O’Riordan M, Malloy EJ, et al. Performance of an automated immature granulocyte count as a predictor of neonatal sepsis. Am J clin Pathol. 2005;123:618–624.