Week 3 Flashcards
what is an intrument limitation vs a specimen limitation
Instrument
-data suppression or parameter flagging
Specimen
-inherent specimen problems that can cause instrument issues
for Cold agglutinins what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected- low RBC, high MCV and MCHC with grainy appearance
Rationale: Agglutination of RBCs
Instrument indication -Right shift on RBC histogram
Corrective action -Warm specimen to 37°C and rerun
for Hemolysis what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - low RBC and HCT
Rationale-RBCs lysed and not counted
Instrument indication - rule of three not followed
Corrective action- Recollect new EDTA specimen
for Lipemia or Icterus what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected- High HB and MCH
Rationale-Increased turbidity affects spectrophotometric reading for HB
Instrument indication - Rule of three not followed
Corrective action-Plasma replacement
for Lyse resistant RBCs with abnormal Hb what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - high WBC and HB
Rationale-RBCs with HB S, C, or F may fail to lyse, will be counted as WBC
Instrument indication -Dense population in Debris (DB) area of Diffplot
Corrective action-Perform manual dilutions, allow incubation time for lysis
for Microcytes or schistocytes what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - low RBC and High PLT
Rationale-Abnormal population or volume of RBCs at lower RBC threshold /or within PLT threshold
Instrument indication-Left shift on RBC histogram
MCV flagged if outside action limits
Abnormal PLT histogram may be flagged
Corrective action-Review PBS for confirmatory morphology
for NRBCs, Giant PLTs, or micromegakaryoblasts what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - high WBC
Rationale-NRBCs, Giant PLTs, or micromegakaryoblasts counted as WBCs
Instrument indication -Dense population in Debris (DB) area of Diffplot
Corrective action-Newer instruments eliminate this error
for PLT clumps/aggregates what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - low pLT and high WBC
Rationale-Large clumps counted as WBCs and not PLTs
Instrument indication -PLT aggregates flag
Dense population in Debris (DB) area of Diffplot
Corrective action-Recollect specimen in sodium citrate and multiple WBC and PLT counts by 1.1 to correct for dilution factor
for Hyperleukocytosis what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - high HB and RBC , HCT incorrect
Rationale-Increased turbidity affects spectrophotometric reading for HB
WBCs counted with RBC count
Instrument indication -rule of three not followed , WBC count may be about instrument linearity
Corrective action
Manual HCT
Manual HB
Correct RBC count and recalculate indices, if above linearity, dilute for correct WBC count
for Old Specimen what are
Parameters affected
Rationale
Instrument indication
Corrective action
Parameters affected - MCV high , and PLT low . utomated DIFF may be incorrect
Rationale-RBCs swell as specimen ages and may hemolyze
PLT swell and degenerate
WBCs affected by prolonged exposure to EDTA (shrinkage and/or swelling
Instrument indication -Abnormal clustering on WBC histogram and Diffplot
Corrective action-Establish stability criteria (retention time) and specimen rejection criteria
what occurs in a TRUE increased RBC count
causes and corrective actions
causes: Polycythemia vera (overproduction marrow), low O2, dehydration, kidney disease, or performance enhancing drugs
-there will be increased pulses through the RBC aperture 30-300fL
-linearity will be up to 8.0 x 10^12 and instead of a number on the Act5 report youll have ++++
Corrective actions- dilution or do a manual HCT and Hgb, recalculate the indices and do a PBF
What occurs in a true decrease
causes and corrective action
Causes: its variable but mostly due to anemia or RC destruction
-system count lower pulses through RBC apeture
Corrective actions are to do a PBF review for morph
what can cause a falsely high RBC count
-high WBC- Leukocytosis
-NRBCS
-large platelets
-platelet clumping
-Cyroglobulins or cyrofibrinogen
what can cause a falsely decreased count
-clot - RBC are in the clot and cant be count - reject and recollect
-RBC fragments - too small or micro spherocytes <30fL so they could be counted as PLT causing a falsely high PLT level - do PBF
RBC Agglutination - bunch of RBC counted as one
what will you see if you have microspherocytes or schistocytes
RBC↓ PLT↑
Abnormal population or volume of RBCs at lower RBC threshold /or within PLT threshold
Left shift on RBC histogram
MCV flagged if outside action limits
Abnormal PLT histogram may be flagged
Review PBS for confirmatory morphology
what is extreme leukocytosis
known as hyper leukocytosis - true increase in WBC in leukimia
-turbid sample due to high count
-in HGB bath - this will cause increased scatter falsely increasing HGB - NOTE WBC are not lysed in 1st dilution bath
-so youll see high RBC and Hgb with invalid HCT
Corrective Actions:
manual HCT and HGB, redo RBC count and indices. If WBC is above linearity - aliquot is diluted and rerun
what are the causes of a falsely increased WBC count
- lyse resistant RBCs like sickles, NRBCs, PLT aggregates
-abnormal HGb, NRBCs, PLT clumps or micro megakaryocytes
what are the reasons for a falsely low WBC
Cell lysis because of
-Prolonged storage
-Smudge (damaged) cells
-Uremia osmotic cell damage
-Immunosuppression
-Fragile leukemic WBCs
Aggregates being counted as single cell- leuk cold agglutinins
True decrease due to disease
CA= manual PBF or morph and a diff
what can cause falsely low plt counts and clumps - low PLT and high WBC
-improper mixing
-microclots
-excessive heparin
-giant PLTs
–micromegakaryoblasts
-underfilling EDTA
-slow or hard draw
-PLT satellitosis- clumping
-abnormal population on SL/SL1 or Debris area on Diffplot
-extension past 20fL
CA
-rerun on mixed EDTA
-new sample
-use Sodium citrate tube and multiply counts by 1.1
What are cold agglutinins and what will we see in a sample that has them
- clumping due to IgM antibodies, but will only agglutinate in cold temperatures
-macroscopically the sample will grainy
-RBC count decreased
-MCV increased (>130fL)
-HCT decrease
MCHC increase (>400g/L) (HGB/HCT)
MCH also falsely increased (HGB/RBC)
RDW increased
Dual population on RBC Histogram or right shift on RBC histogram
what are cryoglobulins
- serum proteins that precipitate out at low temps 4C
-can dissociate or resuspend at 37- body temp - can be associated with myeloma, carcinoma, and leukemia
-affects the same parameters as cold agglutinins
-the precipitated proteins can be so large that you might count them as WBC
-the smear will have a CLOUD LIKE appearance from the stained precipitates
CA- prewarm sample or recollect and maintain sample at 37
what will you see in a sample with hemolysis
- rule of 3 not followed
-red or pink plasma
-low RBC and HCT because the hemolyzed RBC are not counted and MCHC is falsely increased
-Hgb is VALID because the RBC are lysed to measure anyways
-mostly procedural causes but can be hemolytic anemia or liver disease
CA- reject and recollect
What is lipemia
-interfering substance
-plasma is white and cloudy because of high lipid content
-high turbidity that affects spec reading for HGB (also for icteric samples high HGB breakdown in RBC high bili)
-rule of 3 not followed
-high HGB, HCG MCHC
CA
-replace plasma with saline and rerun
what effect does a clotted sample have, causes and CA
- procedural - not mixing properly or hard draw
-micro clots will have impacts on CBC, PLT WBC because theyll be caught in the clots and wont be counted properly
-on a PBF youll see fibrous/stringy light purple substance (fibrin) in the tail and body of the smear
CA- reject and recollect
What are NRBCs
- occur when the BM is stimulated by EPO causing early release of RBC causing immature RBCs to be seen
-increase in NRBCs cause false WBC increase
-all nucleated cells on Act5 are counted as WBC
-the NRBC will lyse in the baths but their small nuclei will remain and be counted causing left shift in curve on WBC/BASO histogram
CA-recalculated WBC
how to correct for NRBC
-if 10 or more NRBC per 100 WBC are counted in a WBC diff then its significant and a correction must be made
Automated WBC count = 11.0 x 10^9/L
Manual DIFF- 10 NRBCs counted / 100 WBCs
100 x Automated total WBC count/L
100 + NRBCs /100 WBC
100 x 11.0 x109/L = 10.0 x 109/L
110
Automated WBC count WAS 11.0 x 10^9/L
Automated WBC count NOW 10.0 x 10^9/L
100 x 11.0 x10^9/L /110 = = 10.0 x 10^9/L
When reporting comment
Comment- ‘Corrected’ adjacent to corrected WBC count
Comment- ‘WBC count was corrected for NRBC”
-Then used the corrected WBC and manual diff to calculate the absolute diff and report
