Lab case 437 interpretation


PH = 7.34, that is very mild acidaemia.

HCO3 = 14 mmol/L. So, we have metabolic acidosis.

Next we need to calculate Anion Gap and compensation.

Anion gap is calculated as: AG = Na – (Cl + HCO3) = 20. So, we have HAGMA.

To calculate the respiratory compensation, we use Winter’s formula. That is expected pCO2 = 1.5 x HCO3 + 8 (+/-2) = 29, with expected range between 27 and 31 mmHg. pCO2 for this patient is 27 (Within the expected range). So no additional abnormal respiratory process exist for this patient.

Because we have HAGMA, we need to calculate the Delta Ratio. That is calculated as:

Delta ratio = ( AG – 12) / (24 – HCO3) = 0.8, this mean this patient has combined HAGMA and NAGMA.

Other abnormal findings:

The most striking abnormal finding is very high lactate of 10.3 mmol/L, (Severe hyperlactataemia.

Creatinine of 159, that is high/ Most probably acute. (Usually police recruits undergo extensive medical tests as part of the job application).

Chloride = 111 mmol/L, that is hyperchloraemia. Most probably is the cause of NAGMA.

Glucose = 10.4 mmol/L. that is hyperglycemia.


This patient was suffering from Heat Stroke.

Hyperthermia is associated with vasodilation with peripheral pooling of blood. This will lead to reduce effective circulatory blood volume. This will exacerbate the high lactate level further. In heat stroke, patients develop sustained contraction of skeletal muscles that exacerbate hyperthermia and leads to muscle necrosis. (Rhabdo).

This phenomenon is caused by nitrosylation of ryanodine receptor 1 (RYR1), which is located in the sarcoplasmic reticulum of skeletal muscles.  Heat stroke deranges RYR1 function and allows calcium to leak into the cytoplasm and this stimulated muscle contractions.

Also, high temperatures can cause cell death. As temperature rises, proteins can unfold, which can kill cells.

These two processes above can lead to elevated lactate, troponine and CK due to damage cells and release their contents.