School of Veterinary Medicine

Comparative Pathology Lab

Clinical Pathology

Automated and Manual Analysis

These services primarily include clinical chemistry and hematology analysis. In addition to routine chemistry screening panels, CPL specializes in performing assays optimized for the micro-sample volumes commonly encountered in rodent biology.

  • Quantitative urine chemistries such as urine micro-albumin, urine total protein, glucose, creatinine, urea nitrogen, calcium, magnesium, phosphorus, sodium, potassium may also be requested.
  • We also offer clinical urinalysis, which includes microscopic examination of urine sediment and urine dipstick chemistries to semi-quantitatively detect glucose, bilirubin, ketones, urobilinogen, occult blood, protein, pH and specific gravity in either random collections from cystocentesis or pooled collections from metabolic cage systems.

Our extremely experienced staff members have the training and mindset to maximize the amount of data we can generate with your limited specimens. We have selected our instrumentation to decrease dead-space assay volumes, so that we maximize the number of tests results obtained per sample. Our computerized analyzer is capable of performing a wide variety of tests, and we specially choose certain methods that are advantageous to rodent researchers. Be sure to inquire about special kidney, liver and cardiac function panels, as well as carbohydrate and lipid metabolism assays, which we specialize in.

  • Our hematology analyzer has likewise been chosen to accommodate micro-samples. The special veterinary software is optimized specifically for mice, rat, feline, canine, lagomorph, ovine, bovine, porcine, caprine and other species. Typically, hematological blood counts, including 5-part differential white blood cell counts and red cell indices, require approximately 30 uL! We recommend that researchers collect 50-100 uL however, for better physical mixing and analyzer sampling. The most common hematological analysis performed is the CBC (Complete Blood Count). These are the following components of that profile:
    • WBC - total white blood cell count in thousands/uL
    • Neutrophils - expressed as an absolute number of cells, and a percentage of the total number of WBCs
    • Lymphocytes - expressed as an absolute number of cells, and a percentage of the total number of WBCs
    • Monocytes - expressed as an absolute number of cells, and a percentage of the total number of WBCs
    • Eosinophils - expressed as an absolute number of cells, and a percentage of the total number of WBCs
    • Basophils - expressed as an absolute number of cells, and a percentage of the total number of WBCs
    • RBC - Total red blood cell count in millions/uL
    • RDW - Red cell Distribution Width expressed as %
    • HGB - Hemoglobin concentration in grams/dL
    • HCT - Hematocrit expressed as %
    • MCV - Mean Corpuscular red cell Volume in fL
    • MCH - Mean Corpuscular Hemoglobin in pg
    • MCHC - Mean Corpuscular Hemoglobin Concentration in g/dL
    • PLT - Total platelet count in thousands/uL
    • MPV - Mean Platelet Volume in fL
  • If a manual review of the blood is desired, a peripheral smear can be prepared by special request.  We use a Wright Giemsa stain for these smears and manual WBC differential counts may be performed on these preparations.
  • Manual reticulocyte counts may also be performed by request.  We prepare the whole blood specimen with a New Methylene Blue supravital stain.
Integra 400
Specimen Collection, Preservation and Transport

Whenever possible, please ship or deliver early in the week to facilitate processing.  We recommend “overnight priority” shipping in insulated containers where possible.  UC Davis campus does not accept deliveries on UC holidays or weekends. This research area’s security gates are locked promptly at 5 pm during the weekdays, unless special arrangements are made. We shut down and clean analyzers in the mid afternoon, so delivery of samples should be early in the day. Thank you for understanding!

Hematology specimens:

EDTA or lithium heparin whole blood is used for hematology analysis.  For accurate cell counts, it is essential that the specimens be clot-free.  For this reason, immediate and thorough mixing of whole blood must occur to distribute the anticoagulant uniformly.  Although complete mixing is crucial, so is gentle treatment of the specimen, as cells are fragile.  Excessive mechanical trauma from forceful syringe aspiration or rapid dispense through a small bore metal needle can create lysis of cells. We recommend the use of BD (Becton-Dickinson) Microtainer brand collection tubes, with powdered anticoagulant inside. Other brands we’ve encountered are Sarstedt Microvette and Greiner Bio-One. Generally, these micro-volume collection tubes are color-coded as, lavender-topped EDTA or green-topped lithium heparin tubes. These present less dilution of the original specimen than encountered with liquid anticoagulants, and generally yield more accurate results.

Ideal temperature range for preservation of whole blood is 2-8°C. Submission to CPL should be during the date of draw and about 48 hours is the longest we recommend to delay before analysis. Cells are also susceptible to freezing damage. Direct contact of blood tubes with ice packs or dry ice can also create severe lysis, which will adversely affect analysis. CBC specimens may be sent with either ice or with frozen ice packs, as long as some kind of insulating paper or gauze is used to separate tubes from direct contact. One of the best strategies is to use an indexed cardboard sample box, which keeps tubes upright and in order. That box can be placed inside a plastic resealable bag and then packed with wet ice or icepacks in a styrofoam shipping box.

Chemistry specimens:

Serum, lithium heparin plasma, EDTA plasma and urine are commonly submitted specimen types.  In most cases, routine clinical chemistries are most often performed on cleanly separated serum.  That is, the clear yellowish fluid that can be collected once a whole blood specimen (drawn without the addition of anticoagulants in the tube) has clotted undisturbed for 30-60 minutes, and then centrifuged to at least 3500 rpm for 10 minutes.  Since rodent blood clots very quickly, some researchers find it easier to sparingly coat the insides of their aspiration syringe with dilute liquid lithium heparin anticoagulant.  This is fine for most chemistries, because lithium heparin plasma is generally interchangeable with serum.   The major exception to this is the assay for Non-Esterified Fatty Acid (NEFA), which utilizes serum or EDTA plasma.  Plasma derived from EDTA anticoagulant may sometimes be used for chemistries, but there are some significant exceptions!  Calcium, Alkaline Phosphatase, Sodium, Potassium, Magnesium, Iron, Total CK are all severely affected by the presence of EDTA.  Repeated freeze-thaw cycles should be avoided in the storage and transport of chemistry specimens.  Generally, if analysis is going to occur within 24 hours, a cleanly separated serum or plasma sample can be preserved safely at 2-8°C, and shipped using standard ice packs.  For storage longer than 48 hours, freezing specimens should be considered.  Please observe postal regulations regarding dry ice shipments.

EDTA Microtainer SST Microtainer

We recommend the use of BD (Becton-Dickinson) brand of blood collection microtainers. These are available from scientific vendors without additives; or with inert serum separator gel; or with lithium heparin; or EDTA anticoagulants.

For your convenience, here are the catalog numbers for blood collection Microtainers, which come in packs of 50 units or cases of 200 units:

Gold-topped tubes for serum collections only, containing inert serum separator gel, can hold up to 600 uL sample volume.  Catalog#  365967

Red-topped tubes with no additive, for serum collections, can contain up to 700 uL. Catalog#  365963

Green-topped tubes with lithium heparin anticoagulant for whole blood or plasma collections. Enough anticoagulant to treat 400 uL of whole blood.  Catalog#  365965

Lavender-topped tubes containing potassium EDTA anticoagulant, for whole blood and plasma collections.  Enough anticoagulant to treat 500 uL of whole blood. Catalog#  365974