Clinical Pathology Laboratory - Frequently Asked Questions

Chemistry

What is the "minimum volume"?

This is the smallest sample volume with which we can perform testing on the analyzer. Please note that the minimum volume does not allow for repeat testing or the addition of tests after the original testing has been performed. 

Commonly Used Abbreviations

LIH – Lipemic, Icteric, Hemolysis Index
This a semi-quantitative determination of the lipemic, icteric, hemolysis index of the sample.  It is a photometric test that assesses the indices.

QNS – Quantity Not Sufficient
The amount of specimen is not adequate for completion of the testing.

ND – No Data
This is a reporting value in the computer-generated reports.  It generally refers to a sample that is QNS or to a test that was not performed.

< or > - Less than or greater than
A < or > symbol before a result value indicates that the value was below or above the reportable range limit of a particular analyte’s linearity.

Coagulation

Commonly Used Abbreviations

DIC – Disseminated Intravascular Coagulation

FDP – Fibrin Degradation Products
Also known as FSP or fibrin split products.  These are an indicator of DIC.
       
PT – Prothrombin time
PT measures factors II, V, VII, X, and fibrinogen of the extrinsic pathway of the coagulation cascade.

aPTT – Activated Partial Thrombin Time
aPTT measures the intrinsic or activation contact pathway and the common pathway.

FIB - Fibrinogen

Hematology

What does it mean when my platelet count is reported as "clumped"?

CBC results are generated by an automated hematology analyzer; however, for quality assurance and verification, every CBC also gets a slide review by a medical technologist.  Platelet numbers are generated by the hematology analyzer regardless of whether or not clumps are present, but if clumps are detected on the slide review, these numbers are considered inaccurate and are not released.  Some variation of "platelet clumping" is reported as follows:

•    "Adequate."  This means that high power field platelet estimates on slide review were 8-12 per 100x hpf and that platelet clumps were also present.  The analyzer-generated number is not released because microscopic clumping indicates that it is inaccurate.  However, because high power field platelet estimates on slide review were adequate, the platelet numbers are at a minimum within reference intervals.  

•    "Clumped, appear increased."  This means that the hematology analyzer generated a count that was above the reference interval and that high power field platelet estimates on slide review were increased (>12 per 100x hpf); however, platelet clumps were also present on the smear.  The analyzer-generated number is not released because microscopic clumping indicates that it is inaccurate, but platelet numbers are at a minimum above the upper limit of reference intervals.  [What does "at a minimum" mean when we're talking about something being over something else?]

•    "Clumped, appear decreased."  This means that the hematology analyzer generated a count that was below the reference interval and that high power field platelet estimates on slide review were decreased (<8 per 100x hpf); however, platelet clumps were also present on the smear.  The analyzer-generated number is not released because microscopic clumping indicates that it is inaccurate, but platelet numbers are at a minimum below the lower limit of reference intervals.  [Here, "at a minimum" means something being under something else...]

•    "Clumped, unable to evaluate."  This means that the high power field platelet estimates on slide review were highly variable with many variably sized platelet clumps.  Neither the analyzer-generated number nor the high power field estimate are released because the severity of microscopic clumping renders both the automated count and slide review estimate inaccurate.

Commonly Used Abbreviations

EDTA –  Ethylenediaminetetraacetic Acid
Ethylenediaminetetraacetic acid is an anticoagulant for blood samples that chelates calcium, thus preventing the clotting cascade from occurring.

Plt – Platelet

QNS – Quantity Not Sufficient
The amount of specimen is not adequate for completion of the testing.

ND – No Data
This a reporting value in the computer-generated reports.  It generally refers to a sample that is QNS or to a test that was not performed.

Urine Dipstick Analysis

Why are the leukocytes, urobilinogen, and nitrates not reported out?

In most cats in absence of pyuria, leukocyte test pads give false positive results and therefore are of no value in this species.  In dogs, leukocyte test pads give false negative test results, even when pyuria is present.  Presence or absence of leukocytes is routinely evaluated using urine sediment.

Urobilinogen test pads have no significant value in the routine evaluation of canine and feline urine.  Do not rely on urobilinogen test pads to screen patients for hemolytic disorders, hepatic disorders, or patency of bile duct.

Nitrite test pads give false negative results in dogs and cats.  Evaluation of urine sediment and/or bacterial cultures can be utilized to determine an infection.