pISSN 2234-3806eISSN 2234-3814
Table. 1.
Summary of the results associated with unreliable automated CBC results
| Cause | Affected CBC parameters | Typical resolution method(s) |
|---|---|---|
| Lipemia | Falsely higher Hb, MCH, and MCHC | Perform plasma replacement and rerun |
| May cause falsely lower RBC count and Hct and falsely higher MCH, and MCHC, |
Report all CBC results or only WBC count, Hb, MCV, RDW, and smear-verified PLT count | |
| Bilirubin ≥25-35 mg/dL or 250-350 mg/L | May cause falsely higher Hb, MCH, and MCHC | Dilute the specimen, rerun, and correct the results for dilution |
| RBC agglutination | Falsely lower RBC count and Hctand falsely higher MCV, MCH, and MCHC |
Incubate the blood specimen at 37°C for 10–15 min and rerun |
| WBC clumping | Falsely lower WBC count | Vortex and rerun, or incubate at 37°C for 10–15 min and rerun, or use citrated blood and correct the result for dilution |
| Platelet clumping | Falsely lower PLT count |
Vortex and rerun, or incubate at 37°C and rerun, or use citrated blood and correct the result(s) for dilution |
| Hyper/paraproteinemia | May cause falsely higher Hb, MCH, and MCHC | Perform plasma replacement and rerun |
| Cryoproteinemia | May cause falsely higher WBC count and/or PLT count | Incubate at 37°C for 10–20 min and rerun |
| Organisms | May cause falsely higher PLT count |
Estimate PLT count and if needed, WBC count from blood smear |
| Glucose ≥ 600 mg/dL or ≥ 33 mmol/L | May cause falsely higher MCV and Hct and falsely lower MCHC | Dilute the specimen and incubate at RT for 10 min, rerun, and correct the results for dilution or perform a micro-Hct and recalculate MCV and MCHC |
| Blood stored at RT for 1–4 days | Falsely higher MCV and Hct and falsely lower MCHC | Reject specimen or report only WBC count, RBC count, Hb, MCH, and smear-verified PLT count |
| Blood diluted with IV fluid infusion | Falsely lower WBC count, RBC count, Hb, Hct, and PLT count | Request a properly collected specimen |
| Adipose tissue (fat globules) | May cause falsely higher WBC count | Estimate WBC count from blood smear |
| Fibrin clumps | May cause falsely higher WBC count or no results | Request a properly collected specimen |
| Small clot(s) | Inaccurate or no results | Request a properly collected specimen |
| RBC fragments |
Falsely higher PLT count | Estimate PLT count from blood smear or perform optical PLT count and verify by smear review |
| Lysis-resistant RBCs | May cause falsely higher WBC count, Hb, MCH, and MCHC | Dilute the specimen, rerun, and correct the results for dilution |
| Hyperleukocytosis | May cause falsely higher Hb, MCH, MCHC and may or may not cause falsely higher RBC count, MCV, and Hct | Dilute the specimen, rerun, and correct the results for dilution |
| High number of giant PLTs | Falsely lower PLT count |
Estimate PLT and if needed, WBC count(s) from blood smear |
| Cytoplasmic fragments | May cause falsely higher PLT, may or may not cause falsely higher WBC count, and/or RBC count | Estimate PLT count and if needed, WBC count from blood smear |
| PLT satellitosis | May cause falsely lower PLT count | Vortex and rerun or use citrated blood and correct the result for dilution |
| NRBCs, megakaryocytes, carcinoma cells | Falsely higher uncorrected WBC count | Manually correct the uncorrected WBC, as needed |
Abbreviations: WBC, white blood cell; RBC, red blood cell; MCV, mean RBC volume; MCH, mean corpuscular Hb content; MCHC, mean corpuscular Hb concentration; PLT, platelet; NRBCs, nucleated red blood cells; RT, room temperature; IV, intravenous.
Ann Lab Med 2022;42:515~530 https://doi.org/10.3343/alm.2022.42.5.515
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