INTERFERENCE IN HEMATOLOGY ANALYZERS

Cold agglutinins

-Parameters Affected

RBC ↓

MCV ↑

MCHC ↑

-Rationale

Agglutination of RBCs

-Instrument Indicators

Right shift on RBC histogram

-Corrective Action

Warm sample to 37C & rerun

Lipemia

-Parameters Affected

Hgb ↑

MCH ↑

-Rationale

↑Turbidity affects spec reading of Hgb

-Instrument Indicators

Hgb X 3 will not = HCT

-Corrective Action

Plasma replacement technique

WBC >100,000

-Parameters Affected

Hgb ↑

RBC ↑

HCT incorrect Abnormal indices

-Rationale

↑Turbidity on Hgb WBCs counted with RBC count

-Instrument Indicators

Hgb X 3 will not = HCT

WBC may be above linearity

-Corrective Action

Dilute & repeat WBC countCorrect RBC countPerform spun HCTPerform manual Hgb (spin & read supernatant)

Hemolysis

-Parameters Affected

RBC ↓

HCT ↓

-Rationale

RBCs lysed & not counted

-Instrument Indicators

Hgb X 3 will not = HCT

-Corrective Action

Request new specimen

Platelet Clumps

-Parameters Affected

PLT ↓

WBC ↑

-Rationale

Platelet clumps counted as WBCs

-Instrument Indicators

PLT clump/N flag

-Corrective Action

Examine blood film for clumps Redraw in Sodium citrate, repeat & multiply result by 1.1

NRBCs

Megakaryocyte fragments

-Parameters Affected

WBC ↑

-Rationale

NRBCs or megaryocyte fragments counted as WBCs

-Instrument Indicators

NRBC flag

-Corrective Action

Count NRBCs or megakarocyte/100 WBCs & correct count

Schistocytes or microcytes

-Parameters Affected

RBC ↓

-Rationale

Size of RBCs or fragments < lower RBC threshold

-Instrument Indicators

Left shift on RBC histogramMCV flagged if below limits

-Corrective Action

Review smear

Lysis-resistant RBCs with abnormal hemoglobins

-Parameters Affected

WBC ↑

Hgb ↑

-Rationale

RBCs with Hgb S,C or F may not lyse & will be counted as WBCs

-Instrument Indicators

interference at noise-WBC interface on histogram

-Corrective Action

Manual dilutions, allowing incubation time for lysis

Leukemia, chemotherapy

-Parameters Affected

WBC ↓

PLT ↑

-Rationale

Fragile WBC fragments counted as platelets

-Instrument Indicators

Inconsistent PLT count with previous results

-Corrective Action

Review smear

Phase platelet count

Old Specimen

-Parameters Affected

MCV ↑

MPV ↑

PLT ↓

Automated diff may be incorrect

-Rationale

RBCs swell as sample ages, WBCs & PLTs disintegrate from prolonged exposure to EDTA

-Instrument Indicators

Abnormal clustering on WBC histogram

-Corrective Action

Recollect specimen