Table 1:

Laboratory results included in the initial work-up and evaluation of a 76-year-old man with pseudo-thrombotic microangiopathy caused by severe vitamin B12 deficiency

InvestigationValueReference range
Hemoglobin, g/L45135–175
MCV, fL11180–100
Platelets, × 109/L68150–400
Leukocytes, × 109/L2.94–11
Neutrophils, × 109/L1.82–6.3
Peripheral blood filmFew schistocytes, moderate dacrocytes
INR1.40.9–1.2
aPTT, s3027–42
Fibrinogen, g/L1.51.9–4.7
Creatinine, μmol/L9264–111
Glomerular filtration rate predicted, mL/min74> 60
Total bilirubin, μmol/L72.83.4–20.5
Unconjugated bilirubin, μmol/L580–12
Conjugated bilirubin, μmol/L14.81.6–8.6
Direct antiglobulin testNegativeNegative
Lactate dehydrogenase, U/L> 4500110–230
Reticulocyte count, × 109/L8010–100
Haptoglobin, g/LAbsentPresent
High-sensitivity troponin, ng/L10< 34
Vitamin B12, pmol/L*< 117138–652
Antiphospholipid antibody screen*Negative
d-dimer, ng/mL*40 052< 500
ANA screen*Negative
Rheumatoid factor, IU/mL*15< 10
ADAMTS13*, %56< 10 indicates severely decreased
ADAMTS13 activity
Anti-ADAMTS13 antibodies*NegativeNegative
Anti-parietal cell antibodies*Negative< 1:80
Anti-intrinsic factor antibodies*NegativeNegative
Flow cytometry for paroxysmal nocturnal hemoglobinuria*NegativeNegative
  • Note: aPTT = activated partial thromboplastin time, ADAMTS13 = a disintegrin and metalloproteinase with thrombospondin motifs 13, ANA = anti-nuclear antibody, INR = international normalized ratio, MCV = mean corpuscular volume.

  • * Laboratory tests ordered immediately upon transfer to tertiary care hospital (day 2 of hospital admission).