CBC options at IDEXX Reference Laboratories provide diagnostic flexibility

By M. Alexis Seguin, DVM, MS, DACVIM


All CBCs performed at IDEXX Reference Laboratories utilize the most advanced hematology technology available. Fluorescent laser flow cytometry methods and veterinary-specific algorithms make it possible to provide automated CBC results with an extremely high level of accuracy in our patients.

All canine and feline CBCs at IDEXX include a reticulocyte count, regardless of the presence of anemia. A reticulocyte count on anemic patients helps to classify the anemia as regenerative or nonregenerative. In nonanemic animals, a persistent reticulocytosis may indicate compensated occult blood loss or underlying hemolytic disease. Early identification and management of the underlying disease process is important for a good clinical outcome in these patients.

IDEXX Reference Laboratories offers a choice of a Standard CBC (s‑CBC) or a Comprehensive CBC (c‑CBC), allowing you to select the best option depending on your patient’s needs. All CBC/chemistry profiles are also available in both s‑CBC and c‑CBC versions. Often the decision of which CBC to select is clear. In some cases, however, a s‑CBC may be selected initially, but after viewing results, it becomes clear that additional evaluation is needed. IDEXX offers both a CBC Smear Evaluation Add‑on test code and a pathologist review, depending on your needs.

s‑CBC (includes reticulocytes)

The s‑CBC option is recommended when performing routine preanesthetic or preventive care screening on clinically healthy animals. For these patients, the s‑CBC is an appropriate and cost-effective option. The s‑CBC option is available for canine, feline, and equine patients. This option provides an automated CBC, including hemogram with reticulocytes (for canine and feline), five-part differential, and platelets.

c‑CBC (includes reticulocytes)

The c‑CBC is the option recommended for sick patients. This option includes the same components as a s‑CBC, as well as a blood smear evaluation by a technician to evaluate for abnormal red and white blood cell morphology, unclassified or immature cell lines, and blood parasites. A clinical pathologist review is automatically included when unclassified cells are seen or when results are markedly abnormal based on specific established criteria.

s-CBC versus c-CBC

* If automated results fall outside of established guidelines and the specimen is considered significantly abnormal, a blood smear evaluation by a technician is performed.
The criteria for a pathologist review were established by an international team of pathologists, internal medicine specialists, and operations specialists and have been endorsed by the IDEXX Medical Review Board.

Options for abnormal s-CBC results

The s‑CBC is generally an excellent and economical choice when performing preventive care screening on a clinically normal animal. Sometimes, however, a patient who appears outwardly healthy may in fact have abnormal CBC or chemistry results. A positive heartworm antigen or tick/vector screen may also be an indication to evaluate a blood smear in an outwardly healthy animal.

IDEXX Reference Laboratories offers the CBC Smear Evaluation Add-on, test code 3900. This add-on code allows you to request an evaluation of the blood smear by a technician on your previously submitted s‑CBC. In those unusual cases where the s-CBC results are markedly abnormal, a Pathologist Review of CBC add‑on, test code 399, is also available.

Making the most of your CBC options

CBC/chemistry profiles with test codes ending in 9999 contain a s‑CBC. For the c‑CBC version, use the same test code minus the 9999.

Ordering options

Test code Test name and contents
375 s‑CBC
WBC, RBC, hemoglobin, hematocrit, erythrocyte indices (MCV, MCH, MCHC), % and absolute reticulocyte count (canine/feline only), platelet count/estimate (automated count if obtainable, otherwise estimate from slide), automated WBC differential (% and absolute neutrophils, lymphocytes, monocytes, eosinophils and basophils)
300 c‑CBC
Includes same components as in a s‑CBC, as well as a blood smear evaluation by technician performed on all specimens for RBC and WBC morphology and parasite screen, pathologist review automatically performed when results are markedly abnormal based on established guidelines or if unclassified cells are seen.
3900 CBC Smear Evaluation Add-on
Smear evaluation by a technician performed for RBC and WBC morphology and parasite screen. Pathologist review automatically performed when results are markedly abnormal based on established guidelines or if unclassified cells are seen.

Note: Add on to a s-CBC previously performed at the reference laboratory. Must be ordered within 72 hours of initial CBC
399 Pathologist Review of CBC
Add-on to a s‑CBC, avian/exotic CBC, or c‑CBC. For c‑CBC requests, a pathologist review is included in the CBC and will be automatically performed at no additional charge if specific established criteria are met (see protocol information in the Online Test Directory at vetconnectplus.com). Test code 399 is not required for the automatic reflexed pathologist review on c‑CBC requests.

Specimen requirements: 1 mL LTT

Note: Blood smear submission no longer required
IDEXX Reference Laboratories no longer requires submission of blood smears. For your convenience, a hematology technician will now prepare blood smears for all c‑CBC requests upon receipt of the specimen at the reference laboratory. However, if you suspect blood-borne parasites, especially Babesia, submission of a blood smear prepared from an ear prick collection is recommended.

Turnaround time: 8:00 a.m.; allow 1–2 working days for pathologist review of CBC if indicated.

Contacting IDEXX

For questions regarding specimen submission or test results, please contact our Laboratory Customer Support Team. For questions regarding individual patient management, please contact our Medical Specialty Consulting Services Team.