Beth Israel Deaconess Medical Center Laboratory Manual

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This section performs cytologic and cytometric examination of peripheral blood and bone marrow, as well as testing for red blood cell, white blood cell, and coagulation disorders.

The CBC is done on automated instruments and includes measurement of the hemoglobin, white cell count, red cell count, and platelet count; the hematocrit is calculated, rather than directly measured, as are certain red cell indices (e.g., MCHC). Many components of the CBC, but not all (e.g., RBC count and MCV) can also be ordered individually. Most WBC differentials are performed using flow cytometric techniques, and allow a high degree of precision in the result (e.g., 78.2% granulocytes). Occasionally, manual differentials are substituted, as when the total WBC is very low or very high or abnormal cells are present. The result is given to the nearest whole number (e.g., 78% granulocytes). A manual differential is done under the microscope and takes longer to generate than an automated count.

For expeditious serial follow-up of patients with WBC <2000/uL, a Total Granulocyte Count (TGC) is substituted for a differential (with the exception of Emergency Department patients, admission differentials and Heme-Onc patients). The TGC is an accurate screen of total polys, bands, metamyelocytes, myelocytes and promyelocytes. More reliable than a manual differential, the TGC can help guide decisions about antibiotics and/or precautions in immunosuppressed patients.

Glass Slides: Microscopic Exam

A peripheral blood smear is only made when a WBC differential is not able to be reported directly from our automated instruments, unless specifically requested by the ordering physician. These smears are saved for three weeks so that further analysis can be made if necessary. Smears with suspicious findings may automatically trigger further investigation by laboratory physician, e.g., blasts, abnormal red cell morphology, excess number of a particular cell.

Smears are also made on body fluids submitted for cell count. Slides with abnormal cells or abnormal profiles (high lymphs, high RBC) are reviewed and, if suspicious, referred to cytology for formal interpretation and report.

The laboratory staff – physicians and technologists – are happy to assist you in review of slides or other material.

Unusual results are further investigated either by review of previous data and/or review of the peripheral blood smear. (For body fluids, specimens with cells suspicious for malignancy are referred to Cytology for formal interpretation and report.) Slides are saved for a minimum of three weeks and the lab staff is available to assist you in the review of patient slides or other materials.

Bone marrow aspirates and biopsies are performed by the Hematology Oncology physicians. Sterile packs are available on patient floors (or can be called for delivery to the floor) and in the Hematology Oncology Outpatient Unit. Trays with non-sterile supplies and biopsy transport media are obtained from the Main Laboratory and the Shapiro Clinical Center 9 Outpatient Oncology Unit.

Stained aspirates can be available for review within about 2 hours. Biopsies, if submitted before 3 p.m., are usually available the following afternoon, except on weekends and holidays. Additional marrow studies (flow cytometry, cytogenetics) may be arranged in consultation with the ordering physician, either in advance of the procedure or after review of preliminary results. Interpretation of the marrow aspirate and biopsy is usually available the evening the biopsy is made available (e.g., if marrow is performed before 3 p.m. on Tuesday, interpretation is available Wednesday evening). Marrows are interpreted in conjunction with a CBC and peripheral blood smear. A patient history and purpose for doing the bone marrow will facilitate bone marrow interpretation and patient care.

A comprehensive menu of coagulation testing is available. When specialized coagulation evaluation is needed, the patient's recent coagulation results are reviewed. We may contact the ordering physician to clarify details about the patient's coagulopathy or thrombotic disorder, including the urgency of the workup. Prior to platelet aggregation studies, a brief questionnaire is completed by the patient and ordering physician as to recent ingestion of aspirin or other medications. Emergency coagulation evaluation should be called directly to 617-667-5227. Ask to speak to the hematology tech leader covering coagulation.

Urine specimens submitted for analysis have a dipstick urinalysis performed and then may be examined on an automated analyzer. The automated analyzer currently in use is the IRIS which uses flow through analysis and image capture to screen urine. The captured images are confirmed by a technologist and reported. Certain results, such as uncommon casts or crystals are verified by manual microscopy.

As urine ages, cells lyse and amorphous precipitates form. We endeavor to process urine specimens as quickly as possible, but the best way to ensure quality results is to send all urine samples to the laboratory as quickly as possible. If urine specimens will be held for a courier pickup or delayed, they need to be refrigerated.

The hematopathology team also interprets biopsies of lymph nodes, fine needle aspirates and related specimens suspected for lymphoproliferative disorders. Biopsies are usually read the afternoon following specimen submission.