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PNH. Paroxysmal Nocturnal Hemoglobinuria. One of those diseases we read about, but perhaps don’t see as often.

Why does it get a disproportionate amount of attention?
Because the pathophysiology is SPECTACULAR!!

Read on to explore.
#valuevignettes 2/
PNH is caused by an acquired (somatic) mutation in the PIGA gene (PhosphatidylInositol Glycan anchor biosynthesis, class A) in hematopoietic stem cells.

This gene is located on the X- chromosome.

Since it is ‘X-linked’, the incidence is?

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M protein ?!?
Ever ordered an SPEP and been uncertain whether to get a UPEP as well?
Should one obtain any other tests?
How does one interpret the results?

Read on for a quick journey evaluating M proteins.
#valuevignettes 2/
SPEP is a screening test for monoclonal gammopathies+ related disorders.
Some indications include:
- Suspected plasma cell disorder (myeloma, amyloid)
- Unexplained
CRAB (Calcemia/ Renal disorder/ Anemia/ Bony lesions),
Neuropathy
- Bence Jones proteinuria

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Patients with iron deficiency anemia generally dislike taking oral iron (nausea, constipation) and often stop taking iron tablets.

Does the way we prescribe ferrous sulfate contribute to this?
Read on to find out. 2/
For decades, the teaching has been to replace iron with oral ferrous sulfate 325 mg thrice a day. Each 325 mg tablet contains 65 mg elemental iron, so TID dosing delivers 195 mg elemental iron to the gut.
Of this, only around 15% (25 mg) is absorbed.

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Ever wondered where the 'ACTIVATED' and 'PARTIAL' in activated partial thromboplastin time (aPTT) come from?

If yes, read on for a quick journey through PT/ PTT testing. 2/
In vivo, coagulation occurs on the platelet surface. In vitro, we use phospholipids to simulate the platelet surface.

The sample used for testing coagulation is plasma, since it contains all coagulation factors.